I tryed something like that as well recently, with server and clients running on the same computer (testing purposes) it worked out well after a while but i tryed to run it over network with my team and it worked but verry slowly.

I think my problem might be the sending for messages to quickly after eachother (every frame).

I did not test this yet but i will when i have time for this.

The western shooter posted a while ago was quite good too, i dont know how this was programmed but it worked out.

I hope someone with a little more multiplayerprogramming expirience can help us out here.