Looking forward to seeing this this system, as one of the 9 renting out 100+ cards. There are plenty of cards which I'd be happy for their prices to fluctuate with demand (it will be interesting not see how you approach this - card price/number of rentals available?). At the same time, got to make sure my Gold Foil chickens aren't rented too cheaply..
I'd probably list around 500-1000 cards in the new system. I'd like to see returns in both DEC and USD.