My Rhapsody is exactly the same way! And it's a mean growl and she's really trying to attack the brush!! I've been brushing her a little bit everyday, until she gets too mean, lol, then I'll stop. I've noticed in the past week she's getting better and better. The first day she only tolerated about 2 min., and tonight she let me do everything except the inside of her back legs (which I was doing last) then did a warning growl at the brush, and attacked about a minute later.
Point is, try brushing a little everyday; it seems to be working with Rhapsody -- she even seemed to enjoy getting her tummy brushed tonight!
Jess, Rhapsody, and Tiger