Sadly, its very difficult to find and I'm not aware of any company that sells the purified protein. There is one company that sells a recombinant version 

http://www.uscnk.com/uscn/Collagen-Type-X-COL10-24393.htm

but this looks very strange as regards its multiple molecular weight bands on SDSPAGE. If you look in the literature, various academic groups have made recombinant versions in the past or purified it themselves from culture supernatant so it might be worth contacting one of them but a lot will depend on how pure you need it to be and from what species.

THANKS a lot. your answer is really helpful! we are also thinking purify it by ourselves.

Sigma sell COLX A1

Hi,

You may kinds of collagen in Alfa Chemistry. The link may be useful.

http://www.alfa-chemistry.org/search.aspx?q=collagen