Well I know about most of those options. I was curious if anyone offered a custom action that would fit the footprint of the xp100 action. Im wanting to build a center grip in possibly 7wsm,7saum or 6.5 saum. But xp100s are getting pretty rare and hard to find. So it im building a custom might as well go with a custom action.
I did just pick up two xps though and one might be a good candidate for a build as it looks like its kinda been tinkered with.
Though I've never done this, I think the primary headache is getting your rifle reclassified as a pistol. I believe this has been addressed in the forum here somewhere. I'm sure someone with experience can speak to this with more insight than myself... But something to investigate.
The definition of "insanity": only being able or allowed to own a single firearm.