Probably a redundant link, since most of us check smbc anyways, but this comic kind of confirms his transhumanist leanings.
I think that comic is more part of the pattern of him covering many interesting-sounding "philosophies", rather than him explicitly endorsing anything in particular. Which is not to say that he doesn't have transhumanist leanings, just that that's not very strong evidence for their presence.
If it's worth saying, but not worth its own post, even in Discussion, it goes here.