RCR sells them as does Superformance - not sure of the others..
From my perspective, it has taken a substantial amount of work to make door boxes work in doors that were not designed or molded with door boxes in mind. The undulating inner door surfaces present an absolute huge challenge to fit boxes which have a lip molded in a single (flat) plane.. I will see if I can get some pictures uploaded and posted here in the next day or so when I get to a real computer. iPads suck at that stuff...