Are there any available adapters for other RDS for the X-Compact?

Compounding matters, a guy at the SIG Academy pro shop just told me that they're rolling out an updated version of the Romeo soon. Not sure how that will change mounting solutions.

I am not sure your concern, the new xcompact is cut for a direct mount for a leapold deltapoint pro, (future) Romeo1 Pro & Romeo2.

The Romeo1 Pro and Romeo2 are not released yet but if they follow the Romeo1 but beef up the components they should be a really great sight. If not you can install a tried a true deltapoint pro.