Maybe the switch type, specifically, that makes 'em costly. The BCD thumbwheels I'd use for setting time and/or other parameters cost less than a buck last time I used 'em. There are bigger ones, and they'd be better, but cost three bucks. They can be accompanied by a segmented bezel that will fit however many you gang together quite attractively and simply snap into place in a rectangular hole.

There are several families of TTL-workalike logic that preserve the function, look, and "feel" of TTL, although you have to set the threshold on your 'scope differently.

Some of those families are WAY faster than TTL, yet use a very small fraction of the power.

At the speed at which you're probably going to be working, the original 4000-series CMOS is probably the best, since you have little output load, and need to be stingy with power. What's more, all that 4000-series CMOS is pretty happy with any supply voltage between 2.5 volts and 15 volts. The stuff won't drive anything to speak of, though, and isn't very fast. The 74C-series is essentially identical, but has TTL functions and pinouts, as well as function numbering.

I don't think you should let this project, or all the comments, intimdate you. Stick with your plan. Use the switches you wanted to use on a mock-up. Try it with the LCD that you've already got. Don't be afraid to use more than one MCU. That will enable you to partition the tasks so they don't step on one another, and MCU's, especially the slow plastic-packaged ones, are pretty cheap.

If you really like it, you can obtain the mux'd LCD's about which I emailed you. With only 30 pins for the both of them, you should have no trouble with pins, particularly if you use an MCU for each. Additionally, there are enough comments on how to implement those encoded rotary switches on yet another MCU. It won't hurt, ... honest ...

RE