I use a front pocket wallet from Fossil. Sadly, it has already gotten a bit Brobdingnagian now. I am strongly considering picking up a phone case with room for a couple cards, reducing the amount I have in my pockets for better or worse I suppose.
I have back issues as well and I use a slim fossil that I carry in my front pocket but am looking for an actual front pocket or credit card holder. I only carry 4 things and if I have cash (hardly ever) I use a separate money clip or ask SWMBO to carry it.
i definitely have saddlebackleather AD. all of their products that i own are TOP NOTCH! i've had my little wallie for a couple of years now and don't go anywhere without it ... either in my front or back pocket. http://www.saddlebackleather.com/frontpocketidwallet
I've been carrying a Ridge for about three weeks now. I like it. I probably have a dozen cards in it and it takes up minimal volume in the front pocket. I got the plastic version in day glo green, it makes it hard to miss.