A few months ago, appleyviper was pissed that someone else has uploaded a copy of the UED mod. He subsequently took down all UED-related models and even was planning to stop modelling altogether. Thankfully me and a few other users could convince him otherwise in the leaving part, but any UED models are now gone from SC2Mapster regardless.
The UED stuff is now online-only. You have search for the UED mod on Battle.net. Type "AVMODELS_UED_(ART_MOD)" to find it right away.
It doesn't have some of the older models though. While unofficial, you can check out the other UED art mods if you have to.