Problem still not solved, however I've learend some things, many of them the hard way.
1.) Connecting an external monitor, even if it's a lower resolution that the internal and even if you have the internal monitor disabled, engages the discrete GPU. Apparently this is normal. (Anyone that knows for sure please confirm or deny).
2.) I wasted a day restoring to factory to see if things were any different. I still got crazy high CPU temps for relatively trivial CPU usages. Anywhere from 20-30% load was enough to push the cores over 100C and fan speeds to maximum. Basically if you're doing anything more than 5% load, temperatures are unreasonably high and battery life is unreasonably bad.
3.) The fact that youtube heads up a $2000+ brand new laptop is certainly a bad joke. However, I did learn that for whatever reason the computer seems to handle youtube (and any flash) in Safari far better than in firefox or chrome. This doesn't do anything to solve the general high temps under any other task but it is useful to know.
4.) I learned that Apple is a terrible, terrible company. They don't care at all about customers and they don't acknowledge any legitimate usage of their products beyond "expensive toys" as evidenced by their slow and incompetent repairs and repair policy. I wasted over a week getting my computer "repaired" and they didn't fix it. That in and of itself is unacceptable if you need your computer on a daily basis for work. I told them it wasn't fixed they denied it. I had to do my own research and digup Intel and Nvidia specs to prove it to them (see next point) then they finally acknowledged there was still an issue. Their solution? A few more days of diagnostics. It's ridiculous the contempt they have for their customers after they churn out shoddy products.
5.) The official intel spec says the absolute max CPU diode temp (aka TJunction) is 105C, my particular CPU: ttp://ark.intel.com/products/64900. At this point the computer will (or at least should) shut down automatically to prevent physical damage. My temps routinely reached up to 104C even when not under full load. This is most deifnitely abnormal. Before reaching 105C and shutting down completely intel CPUs of this type will automatically "throttle" which means to decrease maximum performance in an attempt to cool themselves down. I spoke with builders of custom systems that add additional cooling, do overclocking etc. with this generation of i5 and i7 CPUs. They said: We don't like to see them over 80C at full load, maybe a little bit higher in our laptops but not a ton. Constantly exceeding 90 and 100C is definitely not normal and will cause throttling and potentially decreased lifespan.
It would appear we're not the only ones (https://discussions.apple.com/thread/4029639). Maybe it's time to switch back to Dell, a company that actually replaces faulty products when they can't repair or troubleshoot them in a timely fashion...
Here's a fresh factory operating system. No new software installed except the temperature monitoring software. Under less than 50% load. 3/4 cores exceeding 100C. Incredible!
