I have done some more experimentation with controlling keypad LEDs, and here's what I think... discussion welcomed:

Controlling keypad LEDs as part of the patterns in MCE.ini

This is easy, and already implemented in the latest version. Here's where the problem lies though: when the pattern is over, your keypad LEDs turn off. The keypad control would turn them back on when any event that normally turns them on happens, like keypad slider change, etc... Getting these two modules (LEDs and keypad) to play nice together seems like quite a bit of work and complex, and I wonder if it's even worth it.

Using patterns for KeyboardOn and KeyboardOFF

I have tried this as well... the problem is also that other patterns can (and should) interrupt the keyboard on pattern, but you don't want your keypad flashing on and off. This is basically the same problem as above, there needs to be quite a bit of logic to make all this work together between the keypad and LED patterns. I don't think it's worth it personally.

What I have currently is a build that manages the keypad LEDs normally (either on or off at the desired brightness level), and also allows the keypad LEDs to be used with patterns, but it doesn't do anything about the state of the keypad LEDs after the pattern is over.

PS. I also looked in the bug that causes the keypad not to wake up the device after idle timeout, but this bug is beyond me... I suspect it's in tklock.c somewhere, but I can't pinpoint it.