I actually tend to join crossovers more often than any single-fandom RP. And, crossovers, by nature, usually involve canon characters -- which I've never had too much of a problem with, especially since, in long-running RP's of this nature, the canon characters sort of develop over time into someone they never were in the show due to being shaped by a completely new world and set of experiences to deal with.
One thing I've recently found to be particularly fascinating, though, is the idea of characters that are partially canon and partially OC from the start, which is sort of what happened in my
Fandomstuck RP by virtue of its premise. Basically, the RP is about the personified versions of fandoms -- characters that represent an entire TV show/video game series/etc in its entirety. The majority of these fandom entities are clearly based on their main character(s) and resemble those characters in a number of ways, but they aren't really the same as canon characters because their existence as a fandom allows them to be quite different from that character, and gives the person playing them a lot of room for creativity in regards to how they would represent that fandom. I hadn't thought about it much when first I started the RP, but I've realized now that it allows there to be characters that are sort of canon but also are much like OC's. And what's interesting about this is that these pseudo-copies of said characters don't
need to be represented wholly accurately to the source material, which eliminates one of the biggest gripes people usually have about canon characters -- and, even I've found it to be a lot more enjoyable than playing strictly canon characters, while still keeping what I like about playing canon characters. And, because of that, I actually haven't started or joined another RP with strictly canon characters since starting this RP, because it just seems hard to go back to playing strictly canon characters after finding something that provides a similar experience while being so much easier to play and allowing so much more room for creativity. o.o
I don't know how one would go about replicating that sort of thing in a different setting. I suppose it could be an AU version of a series, thus allowing the players to make AU versions of each canon character and leave themselves room for creativity (then again, I suppose that depends on just how far-off the AU is from the source material). I don't really know; I discovered this interesting little phenomenon sort of by accident, and I just thought it was worth sharing. XD