I went ahead and purchased a couple pieces of BusBoard (from Amazon; free shipping since I have Prime!) and a pile of DIN-41612 VME-style connectors. The connectors have three rows of 32 pins, but due to the BusBoard design, two of the rows are bound to the same bus. Thus the net is 64 wires on the bus. I got the DIN-41612 connectors from Phoenix Enterprises.
Here's what the finished backplane looks like:
There are 7 ports on top for component cards. I also put right-angle male and female connectors on either side so I could daisy-chain backplanes together if needed for more component boards.
I will likely use a setup like this so that I can have the board I'm currently "interested" in be presented face-up instead of stuffed sideways. For example, my first component card will be power, clock and control, and will likely live in this position for a while. In the future, when there are, perhaps, I/O devices like an LCD or keypad, I can chain boards together like this to make a nice tidy system.
When cards are installed vertically, they'll look like this. There's plenty of space between boards for any oversize components.
Here's a close-up of the BusBoard traces. It's really well thought-out: one side of the bus is denoted with the "skinny" traces, while the other side is noted with the "thick" traces. Thus it's simple to position components on the board to ensure you're connecting to the right pins on the bus.
Of course, the bus traces run the entire length of the board, so I'll need to invest in a battery-powered dremel tool or something so I can selectively break traces. I can also stack a non-bussed protoboard over the BusBoard and connect them with standard DIN connectors if I end up in a situation where cutting traces is too much development effort.