Has this been discussed at all by Twilio? MMS rollout over Google Voice has been moving at a glacial pace for years now (although they did add Sprint most recently, so there is 1 person I know who can now send me pictures). I know each carrier has its own MMS system of sorts, so I'm curious whether the challenge is more technical or political.

They don't officially comment on it -- which is different than saying "it's not on our roadmap" like they do with other features -- but with the size of the opportunity it presents, the relationships they have with carriers, and the combined talent of their engineers, I'd say it's only a matter of time.