Opportunity is missed by most people because it is dressed in overalls and looks like work. - Thomas Edison
We normally print logo's on the back in grayscale one color ink because there are so many that way no one's logo out shines the other plus it's a little cheaper...photoshop hit grayscale done, maybe not that easy but you get the picture.
The way I look at it is I make my profit on press. If I have to spend an hour recreating logos for a job that I'll make several hundred dollars on, so be it. It's my decision to do it anyway. I could just use the low res stuff the customer sends and tell them that's the best I could do, but then I'd feel crappy knowing that I could have done a better job and the customer will be less than 100% satisfied with their shirts. Lose-lose situation.