Well Randall, you'll notice that the overwhelming majority of bluegrass flatpickers are playing Martin dreadnaughts, so you should be looking for an axe with those characteristics. Get the best guitar you can afford, string it with at least medium guage strings--heavier if the instrument can take it, and practise practise practise. Yes, you want a bright sound, and you also want a loud guitar, if you're not going to use amplification.

Keep on pickin

DrWord