Maxipedia
Retro Guru
Back in the day, the 735 mm RooX Torque Bar used to be the widest and it also got lifetime warranty. An amazing bar that I still miss, but not exactly for a P20 Ritchey, if you ask me.
On the other hand, FUNN were doing as recent as 2008 a pretty low rise 750 mm Full On bar that Sam Hill was sporting on his Iron Horse Sunday. You might want to check that out and give it a try. I also find the 710 mm Race Face Air Alloy riser that I currently use on my Jekyll to be wide enough for XC and besides that I have a 720 mm Renthal Jump Bar on my MaxMax dirtjumping bike that I absolutely love.
http://www.pinkbike.com/news/750mmFunnBar.html
Mx
On the other hand, FUNN were doing as recent as 2008 a pretty low rise 750 mm Full On bar that Sam Hill was sporting on his Iron Horse Sunday. You might want to check that out and give it a try. I also find the 710 mm Race Face Air Alloy riser that I currently use on my Jekyll to be wide enough for XC and besides that I have a 720 mm Renthal Jump Bar on my MaxMax dirtjumping bike that I absolutely love.
http://www.pinkbike.com/news/750mmFunnBar.html
Mx