Hi Pete,
I shoot reportage style weddings using 1D MK 2 bodies,built like tanks but are very heavy with a ex580 and Sigma 70-200 f2.8 onboard,i'm still thinking of changing to 5D as i used EOS-1V film bodies for years and i miss the huge bright viewfinder full frame camera's have,with the 1D i have 8.5 fps but in reality never use it,a company called "RGB TECH"
http://www.rgb-tech.co.uk/product/1679 are knocking the "5D MK 2 "out for £1799,thats £450 cheaper than anywhere i've seen,my only concern is at 21MP will i then need to go out and invest in a new computer to cope with the huge files,Mart.