I think you'd love an FM2n or FM3A or FE2 -- all manual focus, small, quite reliable and capable. Manual focus, of course, and only center-weighted metering. But based on your description of your project, I think AF isn't needed, or the fancy metering either. And truth to tell, the F4 and F5, though great cameras, are going to be pretty darn conspicuous. The cameras I mention above will be less likely to scream "press photographer" than the big Fs.