By this, I mean XUL Widgets now packages its chrome to be easily dropped into an existing XULRunner application. It’s a beginning step (possibly incorrect, but simple) for building a chrome package for a larger app. I’ll be porting the code used to make this chrome package over to jslib and xpistubs shortly.
UPDATE: JSLib and xpistubs now have code checked in to support XULRunner as well! No new packages generated for jslib yet; I leave that up to the mozdev team.
If you have a xpistubs-based project, drop me a line. I may be able to help you apply the patch to your own project.