Hi,
I had to look back at the opensocial archives to find your original message. It looks like it was attached as a page rather than sent to the mailing list. Perhaps this is why there weren't any responses? Did you cross post to the list as well?
OpenSocial is an open standard, and as such we can't actually prevent deployments that don't take accessibility into account. We could provide guidelines, but these would be the same guidelines that would apply to all web development (as published by many standards bodies and government agencies, as you mentioned). As I'm sure you're keenly aware, few people are following those guidelines anyway, unless they're trying to satisfy a government contract.
It's important to bear in mind that OpenSocial is just a set of APIs, themselves built on top of existing open standards that I believe all have relevant, published accessibility guidelines. If you have specific concerns about the OpenSocial spec that aren't already addressed by the specs that we ourselves depend on (such as HTML, ECMAScript, and CSS), by all means, please bring them to our attention. The specs are very much still in a state of evolution (hence the "0.8"), so there's no time like the present to incorporate your feedback.
--
~Kevin