OK well I have no idea why anyone would think that Half Life will mess up if you are using a model that has more than 2048 polygons, but I had Milkshape for the 30 free days and hacked 3 models, a shotgun, a crowbar, and a 9mmAR. The shotgun and 9mmAR were bother well over 3000 polygons, but if you don't believe me:
http://www.svencoop.com/forums/showthread.php?t=27791And if thats not enough proof
http://www.banana.nu/?section=viewitem.skins.skin.main.352There's a model with over 10,000 polygons.
Also, almost all CZ models are over 2048. I know you are a modeller so I know that you must know a lot about the Half Life engine, but it just doesn't make sense why anyone would think that HL would crash or something if the model's polycount is over 2048, no offense, but it just doesn't add up.