Is there a difference between the TVA 50 and the TVM 50 also where can person purchase a power supply for the TVM 50.
My guess is the only real difference is that the TVM50 appears to be exclusively sold in the EU and Canada.
Though I could be wrong as it's an assumption based on the fact that TVA information isn't available on Panasonic pages for these areas, and TVM information isn't available on Panasonic pages for the US
As far as the power supply, you could check with a distributor, Panasonic, or Ebay (though I'd personally skip the last option)