Does anyone know a way to turn the blue eco gauge lighting either on or off? It was kind of cool/gimmicky at first, but now I find it slightly annoying.

No, Welcome!

After a while you'll forget all about it. I rarely notice it anymore.

Two climate control systems, one inside and the other at the tailpipe.

2007 Camry Hybrid (in service June 2006)
FE: 6.67L/100km or 35.3 mpg (6.11L/100km or 38.5 mpg in summer)

I don't mind it because due to the brightness of the non-nav lighting for the radio/ac controls I have my instrument cluster lighting set to one notch above "off". The brightness of the eco drive lighting helps brighten up the instruments while having the other lighting as low as possible.

For the first few weeks I was infatuated with the ECO Drive Indication in the MultiFunctionDisplay.
Then I quit worring about the FE and let the car do what it does best I switched the MFD to display the tank range mileage indicator and use the colored halos as my fuel efficiency indicator exclusively now.