I was searching around on the web for more info on Traits (I may be needing to implement them or something like them in C#/.NET/MSILasm in the near future). And I actually found this page which has the original paper, along with a technical "experience report" on implementing the Smalltalk Collection class heirarchy with Traits as well as a paper on a formal model for Traits. I am printing them out right now for the train ride home, but haven't read them yet. Ovid, I thought you would especially be interested in this, and maybe chromatic too (maybe even Larry, Damien & the Perl 6 posse as well (assuming they already don't know about them)).

Update:
Just also found this paper (not for the faint of heart) - A typed calculus of traits (PDF). Which came from this page on Lamda The Ultimate.