http://www.swiftech.com/H320.aspx there's that which is the best AIO you're going to be able to get and you cant get 45mm or 60mm thicknesses unless you go with a custom loop. What are your specs because it's likely that you won't need a 360 rad if all you're doing is your CPU.
There is also the H105 which has a 240x38mm rad which also has very good performance.
The reason there are hardly any 360mm all in one CPU coolers is they simply aren't needed. Not when a 240 or 280 is more than adequate for cooling any overclocked CPU on the market.