My mattress is one of those 15 inchers, and I finally went out and bought deep(er) pocket sheets at Sam's Club. My son recently upgraded his bed so I took the memory foam topper off of it just yesterday and put it on my bed, and those sheets STILL fit! I have to jump up a little to get on the bed. Best of all, they were only about $40 for the set, and they're very fine cotton. I think they're these.

Karen