Don't know what it is, but it's a cool looking banjo! I have a few banjos, some, very old, with serious pedigrees, while others seem to be made from bits and pieces of spare parts. One of mine, I know is a hybrid, because I had a neck custom made for it that's quite different from the original neck. Another one is a tenor that's been converted int a five-string. Yours looks like it could be a banjo made from parts as well.