Go for it if you want!
I can follow your expectations pretty well. Although my intention was only to get a rust free chassis and some more daily drivability (e.g. in comparison to a '72 "S"), I would hate nowadays to miss the better seats, power windows, blabla.
But I think its only interesting (moneywhise) if you have access to all the needed parts from an older car. Otherwhise it will get damned expensive.
Jens
'76 2.7 with '73 body conversion
BTW: the 2.7 is still leaking a little, but pulls REALLY like a rubber band!