"...so I was wondering if you had any tips or advice on how to convert D&D 4e to Risus, specifically monsters."
Why yes, dear reader, I do indeed. Converting to and from Risus is a snap and I had been thinking about this very topic for a post before I was pulled in other directions. I have already discussed conversions from D&D in general but I'll see if I can't make things a little more specific to Fourth Edition.
The Short Version
Characters: A character's class (or race/class/variant combo) translates directly to a cliche. All the stuff that the character would normally be able to accomplish as a D&D character now falls under the purview of this cliche. Of course, a player character in Risus typically has more than one cliche. This a great opportunity to work-in multi-clasing, hybrid classes, Paragon Paths, Epic Destinies, unusual skills, special feats, and (especially) non-adventuring backgrounds.
Monsters: At its simplest, a Monster becomes its own cliche. All the stuff that a monster could do can now be acomplished by that cliche. Unlike player characters, Monsters usually do not have additional cliches. But adding additional cliches is great way to make Elite or Solo monsters (more on that below).
Levels: Off the top of my head, I can think of several methods of converting levels. Since I've already explored a direct mapping in previous posts, I think I'll focus on a diffferent approach. Try creating characters using standard Risus parameters (10 dice, limited to only 4 dice in any cliche). Then decides what the equivalent D&D level would be for these characters. In older additions of D&D, a starting Risus character might feel like a mid to high-level character. With D&D 4e (where characters more super-powered), I'm guessing that Risus characters are more akin to low to mid-level characters instead. Ultimately, it doesn't matter. As the characters adventure and advance in their cliches, the D&D equivilent level can be allowed to rise. It can also rise faster than the rate at which the characters gain cliche dice. This a way to get around the granularity mismatch between the two games (6 dice vs. 30 levels).
An example might be helpful. Let's say you create standard Risus characters based on existing D&D 4e characters or concepts using 10 dice. Even though it is not required, it is likely that the characters will each have at least one cliche rated at 4 dice. According to Risus convention, this is solidly in "expert" territory, well beyond professional competency. Moreover, these 4-dice cliches are likely (though by no means certain) to be "adventuring worthy" - something more-or-less akin to D&D character classes.
Clearly, these are competent characters. How competent in relation to 1st-level D&D characters depends on assumptions about the game world. It also depends on the types of creatures you'd like the characters to face. If you're planning on having the characters be fresh from the village newbies just beginning to explore kobold-infested caves, then you might want to set the D&D equivalent level to... let's say 3. All that means is that threats challenging to 3rd-level D&D characters should now be appropriate to your Risus characters as well (perhaps a single 3 dice cliche for stock monsters). A D&D monster that challenges 5th level characters should definitely rate at least 4 dice instead. The exact number of extra dice to add doesn't have to be explicitly defined. Just know that a single die of difference is significant and two dice can be deadly (not counting teams and any other advantages the party might be carrying).
On the issue of monsters, I'd be remiss if didn't address the D&D 4e Monster roles (which I happen to be quite fond of). Leaders fight differently than Brutes and Soldiers certainly fight differently than Skirmishers. And then there is the whole Minion-Standard-Elite-Solo continuum. Certainly, a Risus conversion of D&D 4e should account for these differences. Here are are my thoughts:
Artillery: Obviously, this creature's cliche (primary cliche if it has more than one) should be focused on range combat. I would consider bumping this cliche up by a die and penalizing the monster if it is forced into melee combat (either with a half-dice penalty for lacking proper tools or by invoking When Somebody Can't Participate). Since Risus isn't a tactical game, it is best to use these creatures when there is some kind of narrative feature (a chasm or a tower) that impedes the characters' ability to close to melee range.
Brute: These guys are the bruisers. If you don't use a critical hits house rule, I'd consider inventing one for these guys. I'd also consider using Funky Dice to front-load their threat potential. Like the Artillery, I'd probably add a die to their primary cliche but might balance it with some kind of weakness for non-standard attacks.
Controller: The Controller's cliche is going to give it one of more interesting powers that can be inferred from the stat block. In Risus combat, these will mostly have a narrative effect rather than anything mechanical. But these narrative effects can matter, especially if they create situations where the characters' cliches suddenly become inappropriate.
Leader: In almost every case, these guys will be Teaming up with other monsters. They may also have some non-standard abilities that resemble those of Controllers.
Lurker: These guys are your back-stabbers and snipers. They probably shouldn't be too effective in regular combat but would instead shine in Simple Contests vs your characters for surprise attacks. I'd say that a successful surprise attack from a Lurker (opposed by a character's most appropriate cliche for alertness and quick reactions) could either damage the character or take him out completely, depending on the margin of success/failure.
Skirmisher: The lack of a tactical component to Risus combat would seem to limit the usefulness of Skirmishers. That's doesn't mean that the Skirmishers' hit-and-run tactics can't be described narratively. They may even provide a certain advantages, like closing in on soft back-row characters like wizards or archers.
Soldier: These guys should almost always have at least one other cliche to provide them with combat endurance and tactical flexibility.
Minion: A group of four minions can be represented as a Grunt Squad of the appropriate level, simple as that.
Elite: An Elite creature should be a challenge for two player characters. That means the cliche dice should be bumped up to account for the expected team-up and at least one other cliche should be added.
Solo: A Solo creature should be a challenge for five player characters! That means the cliche dice should be bumped way up to account for the expected team-up and at least two other cliches should be added.