Regarding keris attributed Tok Chu to Tok Chu, perhaps the most useful thread is:
http://www.vikingsword.com/vb/showthread.php?t=7618
Perhaps it sounds harsh, but the information from the thread David linked in previous post sounds like a typical dealers invention with the purpose to sell better their stuff - three completely different keris from at least two very different time periods and quite different quality are linked to a famous name; "tok chu luk, normally with 3 n 5 luk, tokchu pamor, tok chu with 'belalai gajah' with atmost (sic) similar to keris malela" has been "introduced", the Tok Chu now appears to have lived circa 150 years earlier, in a more "magically loaded" time...
Becouse of such "inventions" I am afraid, there are almost none possibilities for a serious research left, and absolutely none in about 30 years for sure.
My apologies for spoiling the business.