So whats the next project?

Originally my plan was to move my traction control switch to my centre console, just in front of the arm rest. I'm not completely convinced I like this though. I'm working on a "custom" switch panel which will mount where the existing heated washer switch is located (between the heated seat switches). I'll be able to have my heated washer and traction control switches with two extras. I'm researching headlight washers. This would use one more of the four switches. Don't know yet what I'd use the fourth for. I'm also in the preliminary stages of adding rear outboard heated seats. I have some switches, I just need to change the backlighting and HI / LO indicators for a proper colour match.

I need to run around to some new car lots for some additional ideas. I'd hate to end up with one switch that didn't have a function.

what about OEM style back up sensors (with the light indicator and stuff)

I've been considering this also. My research to date shows that it is entirely possible to install backup sensors, the display on the headliner and the control module. Where it becomes a problem is integrating it with the radio. The module itself doesn't communicate on the class 2 serial data bus. It connects to an input on a BCM and as you get close to an object, the BCM sends a class 2 signal to the radio to activate the chime. The problem is that the Bonneville RIM doesn't have this input. The Cadillac DeVille RIM is very close to the Bonneville in many respects. It does support this input. The DeVille RIM also supports many of the other options such as ALC which the Bonneville has (and is ALMOST pin for pin compatible). These two cars (the GXP and DeVille) already share several components. I may try installing a DeVille RIM as a test, but it doesn't support the accessory inflator (which I really don't want to give up). I can make the system work, with the exception of the audible chime. I'm just not sure I want to add this if I can't make it work 100% the way it was designed.

Haro suggested RainSense wipers which is another one I'm looking into further.

Your work is impeccable! Next you should add rear steering!

I bet the next thing with this project is that it will come on automatically below a certain temp.

Well, that'* an interesting thought. If RainSense is possible, why not FrostSense!