Hi Finlander, I use power a lot, reciprocating and then rotary with large 'hogging off' burrs to remove the waste wood on my larger carvings. I then hand carve everything until I get down to clean up, then I use rotary again. Sounds like that's what you're after, something to do the clean up with.
If you're looking for detail quality, the money invested in a micro-carver (I have the RAM, like Donna and love it), is money well spent.
If you're just looking for clean up on smaller pieces, I would just buy the flex-shaft to go with the dremel. I have that, in fact I have two dremels, one is fitted with the reciprocating flexshaft, one with the rotary. I hang my dremels from a hook, they don't get any sawdust on them, since they are up out of the way.
Al is right, RPM's are important, not only if you want to do heavy work, but for fine detail work too. There is no comparison between using regular rotary and my RAM, for intricate detail.
Good luck, share some pictures with us, we'd love to see your work!

Deborah