It already exists! Well, kind of... The Forester XT has pretty much the same block, but without the beefed up drivetrain and other STI bits. However, with a few goodies from Cobb or someone else you can make it just about as quick. They don't look too bad either, but I just can't get myself to pull the trigger on a Forester.
'05 or '06 Legacy GT Wagon in Silver with a nice tint and some sexy wheels. Such a sleeper wagon. I'm whippin' the '04 Legacy Wagon right now, so slow but a solid little car.