It's unlikely to happen. Tommy Wiseau is a bit of a... Well he has a strong ego problem let's say it like that. And he holds the distribution rights to "The Room." And while he's "gone along with" - to some degree- the movie's cult following as being so terrible by ret-conning his motivations for making the movie (now claiming it was SUPPOSED to be bad) he's pretty clenched-fisted about the rights to the movie. The midnight screenings that occur at times are only done with his permission (and I believe direct involvement) and a while back Internet personality "The Nostalgia Critic" did a video-review of the movie. Legal action was threatened by Wiseau over copyright claims since the review used clips from the movie causing the review to be pulled (The review is back up now, supposedly someone or a lawyer from TGWTG, told Wiseau about "Fair Use" and that reviews using clips qualify as that. I believe this also impacted the RT sample here, also now back up due to it ALSO being legal under "Fair Use.")
Rifftrax had, in fact, I believe, already approached Wiseau about doing a VOD and he turned them down.
So either Wiseau needs to REALLY lighten up when it comes to the distribution of his movie (which can't be too high right now) or Rifftrax would need to make a very good deal with Wiseau to make the monetary gain overcome his ego (which would mean a higher than normal priced VOD.)
It's not strictly impossible but just very unlikely.
This is all in contrast to "Birdemic" whose distribution rights are owned by another company and are out of James Nguyen's hands. That company realizing "Birdemic"'s "appeal" as a bad movie, hence special edition releases containing a coat hanger, tongue-in-cheek citing of Tippi Hedrin as a guest star on the box art and allowing Rifftrax to use the movie in a Live! event.