The above sources manufacture and/or sell Wilkinson licensed trems, but the real "source" is actually in the UK. Trevor Wilkinson is now affiliated with FretKing:
http://www.fretkingbitz.com/PreviewHTML/P_shop.html
I have no idea if there is any difference in quality between the Fret King distributed units and the Gotoh, Allparts or Carvin-licensed ones.
Incidentally, one thing I have found very confusing is the difference between the VS-50 and VS-100 units. Mighty Mite retails a "VS100" that has a different base and stud spacing that their VS50. But every other trem I see labeled "VS100" appears to have the same base and stud spacing as the cheaper VS50. In fact, even the VS100 on the Fret King site has a base matching the VS50.
Onward,
Bert