I'll try to keep this short. I've got 42 recessed 5" can lights in my finished basement on 4 separate circuits. The one "zone" coming down the steps is controlled by a 5-way (4 switches) and the other 3 have just one toggle switch.
I'm guessing that your "5-way" switch circuit is set up something like this:
???
I'd like to do the following:
1. Control all 4 circuits from a single switch at the top of the steps. I'm thinking something from insteon would do the trick, but I'm not sure.
That's where I'd start. And either of these:
http://www.smarthome.com/2334-232/INSTEON-Keypad-Dimmer-Switch-Dual-Band-6-Button-White/p.aspx
http://www.smarthome.com/2487S/Keyp...pad-with-On-Off-Switch-Dual-Band-White/p.aspx
would be your "single switch" (so to speak, anyway). Which one you want will depend on whether the load is "dimmable" or not. And note that you can have one of these keypads at EACH of the four locations you currently have those "5-way" switches.
2. Add one or more ceiling mounted occupancy sensors to turn the lights out after the wife and kids inevitably come upstairs and leave (42) 60W bulbs burning for three days until somebody decides to play in the basement again.
Easy-peasy:
http://www.smarthome.com/2842-222/INSTEON-Wireless-Motion-Sensor/p.aspx
Is there an RF solution for this?
Not quite sure what you're asking here. Most of the Insteon stuff communicates via BOTH the power line and RF, redundantly. They call it "Dual Band". This is done to enhance signal propagation, so as to maximize total system reliability. The motion sensor cited above uses RF exclusively between the sensor itself and the plug-in interface module (and for that reason, is battery-powered; which I personally view as a minor negative); but that module DOES require a real connection to the home's electrical system in order to function.
3. Replace the incandescent bulbs with LEDs. Easy enough... Just still a bit spendy.
Given the "family habits" you described (which are not as uncommon as you might think), I'm sort'a surprised you haven't already done this.
Thoughts and guidance greatly appreciated.
Note that each of those keypads cited above can directly control ONE load. The other buttons are used to send commands to OTHER load-controllers elsewhere in the home/system, potentially on a "scene" basis (i.e., one button can be assigned to represent a complex combination of settings on a large number of individual devices). Depending mostly on exactly how your current installation is wired, you just MIGHT luck out and be able to connect one physical load to each of the four keypads you will presumably be installing. But if it turns out that this is impossible or inconvenient, then will want to ALSO use something like:
http://www.smarthome.com/2477D/SwitchLinc-INSTEON-Remote-Control-Dimmer-Dual-Band-White/p.aspx
or:
http://www.smarthome.com/2477S/Swit...-Remote-Control-Switch-Dual-Band-White/p.aspx
...again depending on whether the loads are dimmable or not.
If for whatever reason neither of these approaches works out, then you can use some of these:
http://www.smarthome.com/2475DA1/In...emote-Control-In-Line-Dimmer-Dual-Band/p.aspx
or these:
http://www.smarthome.com/2475SDB/In...ontrol-In-Line-On-Off-Switch-Dual-Band/p.aspx
to physically control those loads to which a keypad or wall switch cannot (conveniently) be directly connected.
Finally, as repeatedly hinted at above, you need to decide what sort of loads you're going to be setting this up for, BEFORE committing to the particular devices themselves. With your current incandescent bulbs, you can use the dimmer-module versions; and the end result would indeed be very nice, what with such features as programmable ramp-up/down, preset dimming levels, and so on.
HOWEVER... Thanks to our short-sighted busybody do-gooder politicians and bureaucrats, incandescent lamps are being steadily forced out of existence; so the long-term prospects for this are murky, at best. As it stands now, the type of bulbs you would most likely use in those recessed cans (PAR-type spots/floods) are NOT completely prohibited (only some types of them are going away); so this won't be an IMMEDIATE problem. But the handwriting is on the wall, so to speak; and I fully expect that even these will eventually go the way of the Dodo bird.
For this reason, I would at least strongly consider sacrificing some of the "coolness" features of the dimmable controls, and going with the non-dimmable relay-based versions of the various load controllers from the get-go, so that you can thus side-step the possibility of needing to replace them if/when you convert to LED or CFL lighting.