As for hearing Baker do a version, I'd say cross your fingers that Big Finish manages to talk Tom and his ex-wife Lalla Ward into doing audios together. If they manage that trick, expect a Lost Stories version of Shada to be announced pretty darn fast.
Would BF actually do another version of the same story after the McGann/Ward one just so Baker could do it?
The only way I'd see them doing it is if Baker rerecorded the Doctor's lines, and they were edited into the extant audio production in places of McGann's.
But I don't see the point
I don't think it makes financial sense for them to spend the time and money to create this. I certainly don't think it makes sense for them to attempt a full remount of "Shada."
And why should
they? They have a perfectly acceptable "Shada" that they've been selling for much of the last decade. I don't know what new
Tom Baker would bring to another audio production.