The problem of changing the color of a deck is actually a simple one to solve. I came up with a routine a few years ago on the fly, when a group of regulars at a bar gig of mine, who'd seen a LOT of my material already, asked for something they'd never seen before.
I had a blue deck in one jacket pocket, and a red one in the other. Using one card from the red deck, I did a 2 minute routine with the "red" deck that ended with the backs all turning blue, and the lone signed card being the only one not matching the rest of the deck.
Later, while they were still there and quite a bit more inebriated, I took the card, changed its back to match the deck, and of course changed it back before they left.
My routine is quite original to me, but there's nothing inherently original to the mechanics of the routine at all. I use more acting than sleight-technique to get the job done.
My point is that if you think about it, coming up with a solution to the problem "how do I make the deck change color" isn't all that tough. And what you end up with might be better for you than what you could buy.
Good luck on your hunt.
Pj