60 Minutes (1/1) had a segment on St Kitts/Nevis and Dominica (among so other countries) where passports, and even diplomatic status can be purchased.
To my knowledge, that is not the case in SXM. I went through the process of obtaining residency, which was very time-consuming. It would be nice for others, if the Friendship Treaty simplifies this procedure, but will likely still involve standing in long lines and lots of bureaucracy.