I was rather busy for the last few months(!) on a related project, but I guess now I can have a detailed look at X-Amiga problems.
I hope to have SATA working soon. Regarding keyboard mappings: it's not possible in the current version; the next version may use the full Xorg window system, which should make it very straightforward.
Quite a lot of work to do! In the mean time, check out Cloanto's new KX Light - it solves many of the problems that occur in X-Amiga, plus it's updated to the newest Linux kernel.