Darell,
You need to check out Wayne's Shark/Remora UI. The ones I have messed with are simply low,med & high but I understand you could further segment the output stages with further additional levels. I think it would be a mistake to go to too many. Perhaps Wayne or someone else can provide the verbage of how and when and the "timing" of access to level change.
OK, I'm up to speed now, and understand how all this works (shocking, I know). A power-cycle UI is easier to implement than I thought! And I can see how it could be just the ticket in some situations. Some of the stumbling blocks, as I see them are:
1. Brown outs and "glitches" gives you a new mode.
2. You must cycle through all available modes in the order they are offered.
3. If using a wall wart, it'll need to have very little capacitance so the power can be cycled fast enough.
If a single switch at the wall (with no additional wiring) is mandatory, then this "power cycle" UI is the solution. In situations where the fixture has relatively easy access, I'd still far prefer an additional momentary switch at the fixture for UI control (so you can access modes in a more practical manner without cycling through ones you don't want, and the UI is not affected by dirty power, etc). The main power switch would then just turn on (at last mode) and off. And 99% of the time, that's what you'll want. When you want a new mode, you change it at the fixture.
Cyclic UIs are by far the easiest for anybody to master as there is nothing to learn. Everything it does is offered up in the same order every time - no exceptions. I totally agree that they are idiot proof and most definitely have their place! At the same time, these UIs are the most frustrating for me to use! If I pick up a PAL light, for example, and I want to turn it on low, and then off, I must first turn it on high, cycle to low. When I'm done, I have to cycle through flashing, and then off. Truly, this drives me nuts and is what led me to the wide world of UI design in the first place!
In my perfect world, I'd want the fixture able to house a wall wart and the driver, with a place for the momentary switch to poke through. The fixture is then just fed mains AC power, and is switched at the wall like normal (Additionaly, the fixture can be switched locally if that is more convenient than using the wall switch as is the case in so many kitchen lights where you have to walk back out of the kitchen to turn on the light over the oven, for example!) This configuration works with 3-way wall switching as well, of course.
There is no one right answer, and I'm enjoying the discussion.