Well yeah, I didn't want to start a scanner or digital debate, I was more explaining my reasons for wanting to develop my own stuff.
FWIW I think my scanner and technique is fine, I know my photography could improve (whose couldn't?) but I don't think exposure is too far off, I can 'rescue' some waay over/underexposed shots using the equipment that I have, my problem is more that when everything else is ok I still don't get the shadows and contrast that I want. Again, that can be fixed in GIMP, but i'd prefer to get it right on the negs.
Also, the scanner is fixed and I can't buy a new one, as is the printer, monitor, and software.
As i've said, darkroom printing and enlarging is just out of the question, so imho there's no point in seeing if the 'negatives are fine or if it's the scanner' by wet-printing. I need to vary the parts of my workflow that I can, and scanner can't be varied, developing can.
Taking the scientific viewpoint (btw, I'm an engineer, but a lot of that was science through high school and 1-2 years of uni), the scanner is a fixed input, not a variable, so even if scanning isn't optimal there's nothing I can do to change it so I'll change other things (like developing) to vary the output.

So back to the chemicals: I know most about xtol and rodinal so i'll start with them. One thing I don't get with Rodinal is that it's a "large grain" developer, so why would I use it on my finest films like KB25 and PanF50? OK, by using it on 400, 800, 3200, the grain is going to be so huge that the image will look too grainy. But the whole point of the slowest films are to have the finest grains for über detail, so why would I put up with stupidly long exposure times and dragging the tripod out all the time, just to ruin that nice fine grain? Maybe I'm missing the point on it (maybe it's just a question for the dedicated rodinal thread), or is it just the convenience of shelf-life and other minor plusses that outweighs the grain? (hey, if I wanted convenience, I've got a 7D for that. I'm going film because it's more fun). And from what I've heard (correct me if i'm wrong), rodinal doesn't do shadows nicely anyway, so i'll probably just forget about it altogether...

Xtol looks more like something I should be investigating, any others worth at least reading up on? Xtol's already sounding good for the finer grain, shadow details, and having ascorbic acid also fits with the suggestion of kb25 working better with acidic developers. If i'm going to limit myself to PanF50, HP 400, P3200 on 120 and KB25, Tmax100, Tmax400 on 135, should I be investigating Ilford brand chemicals? Which ones would be a good place to start for someone in my position? (I'd love to read up on all of them, but that's something i don't have time for these days).