I guess no one else here has anything else to say about this.
I heard back from one dealer today and they say they will program the TCU for $330 or install and program it for $578 (an extra $248).
So, it would probably be about $1500-$1600 fully installed by the dealer. Maybe $100-$150 less if I found a local independent stereo installer to do the installation.
A Parrot CK3000 can be had for about $115 and the Multican steering wheel control kit is about $185. So $300 in parts. Maybe $100-$150 labor at most, so for less than $450) I could get that kit with integrated steering wheel controls and, as far as I can tell, the only thing I would miss is having the caller-id displayed on the radio screen. I would probably not activate the BMW Assist function, so that's no loss to me. I would have to use my cell as the caller-id screen.
Not sure it's worth $1100-$1200 more to have caller-id show on the radio screen.
I might consider the ULF kit instead if it isn't too much trouble to learn the German commands.