I cannot say for certain that having multiple domains pointing to your URL can dampen G Local listings, but it does look to be the case.
I know of a couple florists whose organic listings outclass the competitors by leaps and bounds, yet they seem to be dampened in G Local/Maps. In each case, the florist has a number of self-referring URLs pointed to their main listing. They have more indy citiations than anyone else, have claimed their listings and have their LBCs in order.... so it looks like the only differential is the multiple domains.
Some companies do seem able to evade the filter by using different names, contacts, addresses and hosting accounts for each domain.
Oh, good lord, my head would explode!