I might have the same question...
I'm using the MCDSP 6050 Channel Strip, and although the presets are nicely organized in folders, the Reaper it's showing me a loooong list of presets, they have the same order but really hard to find what I'm looking for.
It seems that this might be a Reaper development task...
Oooh, and by the way, after 2 weeks of trying Reaper, I'm a new happy Reaper customer