TVShowsOnDVD.com has reported on a June 15th release date of four mini-DVDs by Funimation, each priced at $3.99 and containing a single episode of one of four shows: TMNT (the new one), Dragonball GT, Yu-Gi-Oh, and our friend Sonic X. The episode each DVD contains is not an exclusive one, though, simply one picked for promoting the series. Look for these at Target stores and 7-11s, and other similar retailers.
You can read the original story and see an example shot of the TMNT disc here.