Here's the standard (and getting a bit over used) "Charging Sonic", this time over an all-glitter background which looks a bit like a cog, or something conducting electricity. The colored collar and cuffs are a nice touch on the T, and the art is large and good quality. This is a small size only.

Snowboarding Sonic?
The same artist from the "15th Anniversary" shirt retruns to lend a somewhat eccentric style to Sonic who is sliding or grinding on a rather abstrat "X" like background. Small size only.

This rather "Matrix" inspired shirt has the Japanese Sonic X logo 'raining down' in the background to a blue glow. They re-use the 15th Anniversary art, but add in 2 other nice poses from Sonic, and the show logo. This shirt looks good white, but it would also be all right on a dark green or black, if they were really going to crib the Matrix. The variant to it (left) is easier to see due to the black background. At the main article you can see the white shirt version.