This is a VERY good time to ask this question!
I used to have the Canon 600 F4 L IIS Mk1 (now 800mm F5.6 L IS) and you need serious support for lenses like this!
The reason it is a good time to ask is that Gitzo have a sale on! It is a serious sale too - about half price - look here:
http://www.gitzo.co.uk/tripods-systematic?o=price
Yes that is brand new Gitzo tripods (direct frm Gitzo UK) for under £400! That is far cheaper than the Chinese copies! Although I am happy with my Gitzo GT3530LS with my 800mm I couldn't resist and bought the GT4542LS - and good though the 3530LS is, the 4542LS is better! They won't last long at these prices so do not delay. What appears to be happening is that they are being replaced by a newer model and tey are dumping "last year's" models. The replacement is £769.96 so £374.98 sounded a little better to me! This is the one I bought, I believe that there is nothing better currently available for your lens and Gitzo tripods last decades of abuse.
http://www.gitzo.co.uk/systematic-series-4-carbon-tripod-long-4-section-eye-level-gt4542ls
This will do all that you need with a 600mm and more. The alternatives from Feisol and Sirui are very good - but not quite as good and much more expensive compared to this deal with Gitzo.
As you may have guessed I am a bit of a Gitzo fan, but that is because I use them and having owned some others and tried many more - I simply don't want anything else!
As to Gimbal Heads, I use the Wimberley2 - hideously expensive, but as good as it gets! There are some very good/as good alternatives out there from the likes of Jobu etc but the really good ones are about the same price as the Wimberley give or take a little. Still if you buy one of the discounted Gitzo tripods then you will have change to get a Wimberley or a top Jobu. Do not cheap out as you will not get the best from this lens, I did and it didn't work.
Regarding the lens foot, I just use a longish Arca type QR plate attached to the normal lens foot and it works perfectly - mine is a Wimberley but others are just as good, it is only a lump of machined alloy after all so any decent quality one will do. I prefer not to use a replacement foot as it may limit your options if you want to use extenders - though I could be wrong!
Hope some of this helps.