Well I obviously listened to Fes and adjusted my backs. I'm having an issue now with the colored pips. Do you like the traditional red and black pips or color matched pips?
Well my original plan was to have four decks.
Royal Blue, Purple, Red and Green with corresponding colors of the hearts and diamonds accordingly as well as the clubs and spades in traditional black.
But now I'm thinking of having one multicolored court and red diamonds and hearts and black clubs and spades.
Traditional red/black is the way to go here. You're looking at a deck that could have great appeal to card players - this would be nice for an upscale poker game. As such, you want to keep certain elements very traditional - card suit colors is a prime element you don't want to change. Keeping the courts uniform from deck color to deck color is also essential - many players use two different decks in play to speed up game play, but they use decks with identical faces on them. It's simpler for immediate recognition.
Ordinarily I might complain about the lack of white borders on the back and how that can limit magicians in terms of certain tricks they can't perform with that design. But magicians aren't your key market - collectors and players are more likely. Collectors love print-to-the-bleed card backs and players won't mind as much either way. Hell, they might even prefer it so when that dingbat who can't shuffle cards to save his life is dealing, you'll know before the first card hits the table whether he accidentally flipped a card the wrong way!
The one caveat regarding the back borders that I would offer is that whenever a deck prints to the bleed in a solid color, it shows off edge-chipping a LOT more than a white-bordered deck would. In the course of normal use, especially riffle shuffles and in some cases faro/weave shuffles, tiny chips of the top and bottom layers of paper will come off of the cards - cards don't last forever and will wear out with use. The chips are tiny, so it's not like you'll see a pile of them on your table, but while a white border will conceal the chipping well due to the white paper underneath, a solid, colored border will make those chips appear much more visible, showing the white underneath as it chips. The darker the color, the most noticeable the chipping will be. Black decks fell out of favor for a while because of this, but they're making a bit of a comeback because, well, let's face it - they look cool fresh out of the box!
Lastly, if there are any additional elements that render the deck backs a one-way design, correct them. Card players won't touch them out of hesitation to be called a cheater. With a subtle but noticeable one-way back, one could arrange a deck so all the sought-after cards are facing in one direction and the rest are facing the other - a common method used by beginning card cheats.