Re: Advice for a potential player.
Absolutely mandolin is used in classical music. It was classical long before bluegrass was created. In addition to the music written for classical mandolin, just about any violin music is possible -- the technique is just different since there's no bow. I just finished a three-day classical mandolin symposium where we played Bach, Vivaldi, Scarlatti and some Munier -- the first three in mandolin orchestra arrangement and the last in its original. There were probably 30 or 40 of us in the orchestra and it was a really great time.
What hasn't been mentioned yet is your interest in the viola sound. The mandolin family has its viola member -- the mandola. It's slightly larger than the mandolin (just like a viola is slightly larger than a violin) and the register is about the same and, from what I can gather (correct me here, guys) it plays the same music as the viola. There are also mandocellos and mandobasses. I'd pop over to the classical section on the cafe and wander through the discussions; and if you want to check out the rock stuff, that's around, too.
If you take the plunge, you'll have a great time.
1920 Lyon & Healy bowlback
1983 Giannini ABSM1 bandolim
2006 Rogue (my toy)
2009 Giannini GBSM3 bandolim
2011 Eastman MD305