GURPS Infinite Worlds: IST, by Kenson and Hite, out now.

[Mamorien]

It's your football, but their version of the IST world seems to be much further down the four-color continuum of super-historical design (with which you may be familiar; introduced by Ken in Wild Talents) than yours, particularly in its shades of Black (moral clarity) and Blue ("the sort of lovely and pointless idea" that accompanies the presence of supers, but doesn't obviously stem from them). Plus, it seems to be sitting on a much more active quantum faultline. It might be possible to reconcile them, but it looks to me like at least one of them is going to get bent out of its previously-stated shape in the process.