enough pixels to print A1 or A0 (canvas)
Suggest a minimum of 8MP, more is better. If 8 MP, then use something like Genuine Fractals (PS plug-in) to rez up images is essential.
Any of the current Canon/Nikon semi-pro or pro bodies. Sony A700/900 also.
would be useing in good light mostly, but good 800 iso capabilties would be nice!
Most D-SLR bodies, D200 notoriously more noisy than most @ 800 and above.
weather sealing would be great!
Canon 1 series, Nikon D2/D3/300 series. Sony A900, A700 only partially sealed.
price not over R15 000!
All above, some required secondhand like Canon 1D, Nikon D2 etc.
Only bodies I can think of now that will fit all your requirements are the Canon 1D MkII/N, and Nikon D2X used, unless you stretch the budget.