Some updates on this! I've read through much of the documentation of FNA (the porting framework we're very likely to use), and it differed from what I expected in a major way: it was not well suited for developing parallel to the regular XNA build. This doesn't mean it's harder to port, but it probably means the porting work is less reusable than I thought and that it will be much harder keeping it up-to-date. The original plan was to give the porting a shot before we continue on with the story, but the new plan is to clone the project on the next stable build, and then I'm going to make porting a side project that I work on during moments where I wait for art, or during my free time, etc. When I've got a port of that up and running I can assess what to do from there! If it was straightforward enough, I might keep making "new" ports for every Stable build, at least.