I'll check the temperature tonight. With the Platinum Extremes, there is no 4"x4" box. Instead, there is a round transformer cover (probably part of the transformer itself) that has a height of 3.5" and a diameter of 6".
You've actually seen pictures of the internals before as I've posted them here. However, here they are again:
http://s128.photobucket.com/albums/p197/kmueller13/P1010169.jpg
http://i128.photobucket.com/albums/p197/kmueller13/P1010171.jpg
http://i128.photobucket.com/albums/p197/kmueller13/P1010172.jpg
http://i128.photobucket.com/albums/p197/kmueller13/P1010174.jpg
http://i128.photobucket.com/albums/p197/kmueller13/P1010176.jpg
http://i128.photobucket.com/albums/p197/kmueller13/P1010178.jpg
The issue with D5 is known. I'm hoping that it's due to me running 6528 tubes for a short period of time. It hasn't gotten any worse since I stopped. Of course, Mikhail ok'ed running those tubes for up to 3 hours at a time. D5 will be replaced soon.
Edit: Oh yeah, while I can't see much of the transformer including a model number, I can see that Plitron's web addy on it.