I thought I'd give you a hand looking and I can't find anything at all.
There are the COBJs in for tempered items, but I can't find anywhere (scripts, fragments) where values are changed.
I was poking around in the Blacksmithing tutorial, but couldn't find anything in there either.
The Form object has a GetGoldValue function, but no SetGoldValue. Maybe hardcoded in the game?
I thought it would be interesting to see how they added the tempered designators (superior, exquisite, etc.) to the objects displayed name, but can't find anything on that either.
Thanks for the effort

Appreciated.
I have done some more searching, and here is what I found so far about tempering:
There are settings name sHealthDataPrefixArmo1 to 6 and sHealthDataPrefixWeap1 to 6
These strings give the 'flaweless' and 'epic' names.
There are also settings named fHealthDataValue1 to 6. I'm not sure what they do, but when I changed fHealthDataValue6 from 1.6 to 100.6 all my 'legendary' equipment turned into 'epic'. So I guess these are the values that determine what name-range your armor is in.
Nothing related to money tough...