This was something I was working on before I got sucked into the mega-move and remodel. I was finding it helpful to learn chord theory on a mandolin and ditch the books. Also, playing chord changes against a guitar (or other lead instrument) was helping me get the hang of it, mostly playing long steady notes with the full bow at low volume. Not what you'd want at a jam for most stuff, but it was a good learning tool, I think. On the other hand, no other instrument family can quite pull off those long smooth notes.

Months ago I was trying to figure out backup playing while jamming with musicians FAR superior to myself (since I am no where near ready for a break or anything) and sort of devised a mandolin chop on the fiddle. Apparently, this is nothing new or innovative :) But now that I recognize it, I hear it a lot in bluegrass playing. The bonus about this was that a bad note is quickly gone and forgotten.

Backup is definately harder. The instrument just isn't designed for it, but done well it makes a sweet addition to many tunes.