What are you using for a bezel now? I originally had the OEMauto bezel without volume since the RA1 / RA2 bezel was not a very good looking of compatible fit. I bought the one without volume for 150.00, yes ouch. I see you have the 7 speed already so for around the same cost you would have full factory controls of the radio, not just volume. Their are many other functions provided, ie mute, screen off, back, engineering mode, dealer mode, scroll to name a few.
The only thing I personally miss from my manual controls is no hard buttons to adjust the airflow, so you have to do it from the touchscreen only.
But to each his own, I sold my oem bezel on here with an extra set of steering wheel audio controls for 125.00, my cost originally was 275.00 for those. I think a lot of folks who bought them with or without the volume control think no one would buy them, but that may not be the case.
Maybe Rick's Ram will sell his, perhaps cgeorgemo will sell his. As far as reverse engineering their volume switch it could probably be done, but the cost doing it, would it be worth that? I think given the choice very few folks would go that way anyways even if they had the 4 speed set up, as I did, it was not really that hard to convert and so much nicer.
But to each his own, and I would be the last person to criticize anyone for that. I think if you posted a wanted listing for the oem bezel with audio controller you would get a few hits from folks who have one laying around, and get it for a fairly good price at that.
GL