If you can sell 500 units, then sell 500 units.
Here's another marketing angle.
http://www.noiseland.com/soundtrax.html
Seems like you could DIY something similar. Lets you sell downloads at the gig.
I think it's going to be a hodge-podge for a while. I still buy CDs as well as vinyl.
No cassettes or 8-tracks though.