Cels Forum

Go to pretty much any online cel shore, and there's most likely
a Tamahome cel for sale.  Although, I do suggest:

Anime Asylum (http://www.asylum-anime.com/)
  They have a lot of FY cels, although only a few Tamahome ones.

and Anime Taro (http://www.anime-taro.com)
  They also have a ton of FY cels, but it there is added cost
  for shipping since they're in Japan.

Also, keep looking on E-bay.  A good deal comes up every now
and again. ^v^

Hope this helps a bit.