Lovely news for all gta 4 players!
(with a copy of gta 4 on steam)
Found a way how the iCEnhancer is working on an actual patched version of the game so you can play it in multiplayer.

Simply paste the "iCEnhancer 2.1 files" folder
(not the folder with the 2 xlive dll´s)
in your "steam/steamapps/common/grand theft auto IV"
folder.

Than start your gta 4 and one singleplayer mission once.
You will experience the usual gritty (ger.="grieslig") bugs.
Close the game and delete the game in your steam libary
[right-click on "Grand Theft Auto IV" and choose "delete local files"/
"lokale daten löschen")]

Than install gta 4 again via steam.

Have fun!

I have tested this on two systems only, but on both it works satisfyingly.
There is only a red sky bug, but only in some areas of the map, and only at a certain "location". Personaly i don´t mind cause´ i can immediatly adjust my view by some degrees.
The rel. high frequency of skybugs you can see in my video originates from the gta videoeditor.
I experience a lot lower frequency while playing.