Here's a list of sources for microbial cultures that I put together a while back:
Some of the links may be out of date by now - let me know...
If you really can't find a strain at one of the educational suppliers, your best bet may be to contact an academic lab that is working with the strain, and ask them for a sample.
If that doesn't work, your fall-back option is always to order from one of the official culture collections, like
ATCC - the American Type Culture Collection. But those are (a) rather picky about who they sell to, and (b) expensive. If you're not at a community lab that is official enough to pass ATCC scrutiny, ask around for a local community or university lab willing to put in an order for you if necessary. Most strains that ATCC sells are around $300 each, but their type strains are often cheaper, around $50.
The best solution for the DIYbio community would be for a few labs with access to BSL2 facilities to reisolate a range of interesting bacteria, so we can distribute them to the rest of the community without the craptastically onerous Material Transfer Agreements that "official" culture collections impose. Looking forward to starting to do some of that as soon as we get our BSL2 facility up and running at Counter Culture Labs...
Patrik