Just going to show this article for those of you who havn't seen it http://www.gamingnext.com/articles/index.asp?id=17&page=2
So mayby the esf team easy can make ESF for Half-life 2... I don't know, just wanted to show that..Gabe Newell - We learned a lot through our experiences with TFC, Counter-Strike, Day of Defeat, and so on. This engine is much more MOD'able (if that's a word) than Half-Life 1 was, and the tool set has been improved a lot. We'll also be releasing a bunch of material to help MOD teams get their existing work up and running on the new engine as a starting point