I believe the CP-E FMIC incorporates an oil cooler, similar to what you're suggesting. Interesting idea though. I like the ER one myself.
Don't really agree with the "BMW tax" comment however. If I was making widgets I know I'd want to be paid for the time and effort of R&D as well as the material to make it.
Besides, if you're driving a 335i you should probably be able to spring for an $800 oil cooler with no hassle
