We do not have GMod servers as they are very hard to make. We already have CS:S, TF2, DoD:S, CoD4/5, INS, and BC2!! I doubt we can make any servers for GMod. They require a LOT of resources.
As the others have said, eGO does not support GMod. A single instance of that game would mean giving up a number of our servers; it is not worthwhile for us to pursue at this time. Please use the Miscellaneous Game Discussion subforum for discussion instead.