Even if the motherboard is wire-wrapped (if WW will work at all at these speeds), it should be done on perfboard with plated-thru holes and a plane on at least one side, like this one from Twin Industries:
Edit, leaving the old URL to rattle their cage:

This lets you solder a chip capacitor from a pin to the surrounding ground plane. This board is less than $20US for 4.5"x6.5", and less than $12US for 4"x6". 4"x10" is priced at $23.60. They also have ones with planes on both sides for the same prices, which is way cheaper than Vector used to have them.

If the mother board doesn't have a ground plane, I don't think cap.s between the pins will do much good.

_________________
http://WilsonMinesCo.com/ lots of 6502 resources
The "second front page" is http://wilsonminesco.com/links.html .
What's an additional VIA among friends, anyhow?

Super-short is not absolutely necessary, but if they're not so short, you have to closely control the characteristic impedance of the transmission lines, terminate them properly, etc.. It's done all the time in commercial designs by engineers who are very familiar with this stuff and have an inventory of test equipment available to them that's worth more than my house; but for us hobbyists and midnight engineers, it's better to stay out of that territory by keeping connections really short and observing "good engineering practice." (Don't you just love that nebulous engineering term we use when we don't have what it takes to accurately model a circuit.)

_________________
http://WilsonMinesCo.com/ lots of 6502 resources
The "second front page" is http://wilsonminesco.com/links.html .
What's an additional VIA among friends, anyhow?

To summarise where we are with this:
- not a lot of expressed interest, so even a run of 6 boards is a bit of a risk
- which makes in tempting to include everyone's wishlist

So perhaps just the preprogrammed non-volatile FPGA for a few dollars makes more sense, and let people get on with their own board design.

That is, presume that it's the FPGA/verilog which is the stumbling block, not the surface mount (or the 3V interface).

I'd be interested to hear more details from the voter who wanted 'something else'.

Cheers
Ed