With a de-soldering station, removing caps is quite easy. You still have to purchase new caps and also need a solder station to put them in. It works quite well but there is cost and time involved.

I agree with you about the last board. The lack of ISA can be bothersome for a DOS gaming machine, unless the onboard audio has good SB compatibility. But it will probably still be worse than a cheap AWE64.

The Abit PX5 looks very nice, but the unknown QDI motherboard looks very promising. Intel chipset, decent number of SIMM slots (if you decide to go with that), accepts ATX PSUs and seems to be very nicely built. I'd have a go with it and fall back to the PX5 if you are unhappy with it.

think the tx pro ii is a pc chips m571, in which case it may be worth keeping - redhill guide certainly gives it a good writeup.. well kind-of:

http://redhill.net.au/b/b-99.html

I have a busted M571 stored and did some reading about them when I got it. Pay attention to the little "Update" on the M571 on the link ratfink provided.
BTW, the sound chips on the MoBo says PCI, but it is ISA. And SB (Pro or 16, can't remember) compatible. And has onboard video too, though I do not know if it has decent DOS compatibility.