I'm afraid I don't actually have any good links, and this is all horribly anecdotal, but hang with me a sec:
There was a recent (within the last year) news story about how Pennsylvania allows registration of vehicles to owners who don't actually live in the state, and how this seeming loophole was assisting in the theft of vehicles in New York, primarily on Long Island. I don't really know how that scam worked, but it got me thinking: if I can register my car in PA, then I could take the front plate off, right? w00t! (I live in Joisey).
I've been perusing the online PA DMV code, but I'm having trouble deciphering the legal-ese; I feel like a dog looking at a clock. Does anyone have any plain-english insight here? Much appreciated!