I believe that the latest news about the League was that found in WoR Supplemental which detailed the HW Clan raids post Jihad and the IE book which mentions it sparingly. The former book also seems to point to some unspecified trouble taking place in the wake of these raids.
What is really strange is that they seem to have fallen off the radar in the post-Jihad era, which gives the impression that they have become isolated. As for the Escorpions, they basically can't even control their own subjects, let alone assimilate others, in even greater numbers. I think that the biggest threat is a HW clan invasion force (which will also probably target the Imperio). Having said that, it would be a shame as the League is quite different from other realms (political setup, economy etc) and could be fleshed out a bit more.