yeah, um, www.autotoys.com is pretty darn cheap, but the customer service is questionable too.
I didn't have any problems, and the forum was semi-helpful...so I don't know...but the unit I bought was cheaper here than etronics.
I think the JVC decks will do what you want. As long as you name your folders 01_Hip Hop, 02_whatever, you can go directly to folders 1-6.
Oh, and a good site for this info is:
http://www.highwaymp3.com