Each tow bar manufacturer has its own design for attachment to the baseplate. There are adapters available to match some tow bars from some manufacturers the baseplate from other manufacturers.
RVUpgrades is an excellent source for Blue Ox tow bars, baseplates, and accessories.
Check the irv2.com classifieds, eBay,
Hitch Trader, etc. for used baseplates. The 2006 and 2007 Vues should use the same baseplate, but it hasn't been around that long for there to be many used ones floating around.