Back to the original topic, basically what Alan is looking for is a TMax 100 with more pronounced edge effects. Other than a possibly higher propensity for edge effects with dilute developers like Beutler (not sure as I have not seen equivalent data/tests with TMax), I fail to see how Pan-X offers anything over TMax. In terms of granularity, speed, and exposure scale, TMax has it beat on all fronts. Some further experimentation with developers may help with perceived sharpness, but this is a very complex thing and subjective impressions cloud judgement. Not to mention the tendency to glorify by-gone products and compare the working characteristics of current films with somewhat inaccurate memories of older films.
Bill - Chromogenic films still show graininess (ie micro-variations in density) in the print. It's just dye clouds instead of metallic silver. If you want a long exposure range, the tonality of a general purpose film, and the finest grain in small format, you're "stuck" with TMax 100.
Thomas makes a valid point regarding sheer resolving power. There are things which can work against the benefits of the larger film size. Camera (mis)alignment, inaccurate focus, excessively small apertures, film flatness, slow shutter speeds. But in the end resolution is only one of the elements of sharpness or image definition anyway, and not necessarily even one of the most important ones. Image quality is a complex thing. 35mm and 4x5 don't look the same, but everyone has to decide what works for them.