There are several pin bushing OD/ID combos available that can be used to get you close to the Mopar OD and Chevy ID in a quality Bronze material, such as from Crower, Carrillo and others like that. The ID will still need to be pin fit once installed. The ID of the piston may need to be honed to allow the correct press fit for the OD of the bushing also, but not an issue.
As for the aluminum bushing idea, it is an option but would likely be considered a custom job, and then you start creeping back up on having a lot of money invested in a $9 or $10 piston quickly turning into 3 or 4 times that once it has to be handled that many times.
