Here's my 9 speed/10 speed mismatch: SRAM 9 speed chain, Tiagra Shifters, Tiagra Crankset, Tiagra Cassette, Ultegra 6600 FD, Ultegra 6600 RD. This is easy to set up and my shifting is MUCH better than when I was using the Sora FD and Tiagra RD.
Also, I have done a good amount of reading on the subject, and the Tiagra Crankset should work fine when I decide to upgrade everything else to10 speed. This setup is working so well that I don't know when that will be.