I can place the 3 way switches either beside or in combination (expand the box in some cases) with other existing wall switches, and I guess use their power. The 3 ways must be dimmable, maybe from both sides if that's possible.
I also have places for some wall switches to run some outlets, if that can be done.
I want to stick with almond decora style switches and outlets if possible.
I don't know how the cans are wired, but can't imagine it would be anything but the simplest in-line wiring based on other electrical screw-ups. Like your first can light diagram. But separating them out by the 2 and 3 seems less important compared to 3 waying them.
Your last post specified "almond". My current home has almond as well and that rules out X10 brand hardware (only available in white and ivory).
The following components are Insteon devices from Smarthome. Insteon communication is relatively new, more robust method of networking switches. They are also backward compatible to X10. These are not inexpensive components.
Remote controlled outlets - replace your existing outlet with a 2473 (new device-available 12/17) and control it with a 2476 relay switch. The switch will not need to be physically connected to the outlet, it "transmits" ON/OFF commands across your wiring with X10 or Insteon communcation.
2473 Outletlinc Link 2476 Link 3-Way Lighting (dimmable) - replace one of your existing dimmers with a 2476 Dimmer (direct connected to the load). Add a second 2476 dimmer (transmitter) in another location to create a "virtual 3 way" circuit. Both locations will have dimming control of your lights.
2476 Link 3 Way dimmable with a controller: This is actually an easier install than the above. Replace one of your existing dimmers with the 2476 (as you did above). Replace a second dimmer with the 2486 (it can dim a connected load). Use the secondary buttons (smaller buttons) to control other "virtual 3way circuits (outlet, dimmable lamps etc). Not decora, but it combines multiple functions, it's easier to install (don't have to "enlarge" switch boxes), and it may well be cheaper than multiple decora dimmers.
2476 Link 2486 Link Signal Linking: You may want to figure in a pair of SignalLincs as well. Your house is (likely) supplied with two phases of 120V power. Roughly half of your home will be on one phase and half on the other. Both Insteon and X10 communication have trouble "crossing" from one phase to the other (devices on the same phase communicate but can't reach the other phase). Insteon uses a RF link between the SignalLincs to establish communication across these phases. Note - you may not need these if all of your devices are on the same phase. Also, if you are planning on using the X10 compatibility mode (I have done this) the signal coupling equipment will be different.
2443 LinkGiven your requirements (almond, decora) I believe this is the most cost effective solution. Leviton does make a X10 line of switches that would also work (I have both Leviton and X10). Problem is, the Leviton X10 decora transmitters are quite expensive and they are more prone to signal problems ( X10 noise susceptibility).
Have a look, generate a shopping list ($$) and get back with any questions.
Boiler