Metalwario64's Blender model IS intended to be released to the public. He just meant to touch the SA Sonic model up a bit and standardize it for public use, and has just stayed busy with other things and forgotten from time to time.
It's an HD-ified Sonic Adventure 2 model with some original additions like new hands. There's also a simplified version more in line with SRB2's art style.(
Imagine spriting those original shoe soles) Because this SA Sonic model was specifically made for learning Blender and to reference for sprites, it's not exactly out-of-the-box ready.
Metalwario has considered releasing it mostly as-is if people are interested in that, but otherwise wait a little longer!
Yes and no. Adventure Sonic doesn't natively create rails in vanilla SRB2, buuuut...
Oh, look, a beta dying animation!