I had the same desire that you do a while ago. This is what I did.
I already had a 580EXII. The Canon flash can be the master but it has to be either on the camera or at least on a long hotshot extension cable to talk with the camera. That could be a solution if you don't mind the cable.
I purchased a Yongnuo YN565EX, which is a low cost copy of my 580 flash. It has the same settings and more or less the same controls so you don't need to remember two ways to operate. You can also use it as a backup to your canon flash with full ETTL functionality. It does not have high speed sync and it can not be used as a master flash but for 95% of what I do it is fine and it only costs $100 USD.
I then got two PixelKing Receivers, and one transmitter the PixelKings support ETTL mode and remote manual control of the flashes.
Two stands, two white, shoot through umbrellas and inexpensive mounts. I am very happy with my setup. I usually shoot with the flashes on manual, but, like I said, having the Pixel Kings and smarter flashes lets me control the flashes from the camera. I find this a lot easier than having to go to the flash to adjust them. I usually shoot through the umbrellas, so the flash backs are pointed up and usually over my head which makes them hard to adjust.
That's what I did and that's what I would do again. Actually, I might not spend so much on a Canon flash and just go with two YN565EX units. I think they have a newer model that copies the newer Canon unit that you might want to take a look at.