Whether the Spinergy wheel works with 10sp Ultegra or not, I'm not certain. What I do know is don't get the Spinergy! They're heavy, ride like **** and the flat carbon blades are great at slicing flesh. I haven't had the unfortunate chance to find out the Spinergy's slicing capabilities yet but I can vouch for the weight and crappy ride quality.
Don't do it, go with "regular" spokes. There's so many other wheel selection out there, even on ebay.
My 2 cents on the matter.