Well, I was just looking over the REST API documentation again, and the real question is, if and when will the MySpace RESTful API support Low-REST; that's what Flash needs to access the API completely.
Framing the question that way may get a better answer.
I'm going to try to scrape together a PHP POST-to-PUT proxy script this weekend - I have to do most of the work anyway, for something else. *ETA* I suddennly know why you never finished this, Brock. cURL does not like sending PUTs across to the RESTful API. I'm still looking into alternatives, but I wanted to update this in case someone was waiting on it.