Where would you be able to find out if a car had previous frame damage or other major repairs besides carfax??

None of this data is reported to any government agencies or other private companies except for insurance companies. The insurance companies will not share this data (they don't even provide it to Carfax - Carfax goes to many other sources to gather this). Carfax is the only place that aggregates the data and makes it available for purchase.

You best bet for more detail is a mechanic or a shop that will actually test/check the frame - but that can be expensive.

look at the frame yourself .. might take some getting dirty but u will see where they welded the frame together... as for like door panels and side panels .. all you have do to is open the door and you will notice marking etc.. on it .. that is how i found out that my car was in a accident 2 years before .. the frame was welded in the back left side under where the truck is at .. i went to the dmv asked for a record on the vin if there was any police reports on it and found one... but they wont just give it to you with out just cause... or take it to some one you trust that will be honest and tell you...

if you know a really good mechanic who will be totally honest with

you then you are in business. a hands on inspection by someone

who knows their stuff is an invaluable tool.