In among all the r.i.p.'s for famous personalities it is nice to hear that there's one Kirk Douglas who has today hit the magic ton Yep 100yrs old today.Congratulations to him well done that man!!
It seems to me that you have in essence answered your own question.You've identified the model and spec you want and are prepared to wait at least a reasonable length of time to find it.Failing that buy the best bodied automatic you can find and swap gearboxes,even taking into account the other bits beside the gearbox itself I would think this to be the cheaper/easier option as opposed to going the engine swap route.I cannot speak from experience as I've never done this-I think the manual box on Omegas[and the Senators before them] is an awful device-but it's each to their own.
It quite possibly is a sales gimmick,but like I said it's very distracting and takes up nearly 50% of the mirror I'd hate to have to buy a replacement in a few years time[once the warranty is out]when the original goes fubar
Been in a 15 plate Megane today-it had badges on front wings saying Limited-when I first got in I thought there was a fault with the interior mirror.From the drivers side[right hand drive] to nearly half way across the mirror appeared darker than the rest.When I started the car however this darker side became a display.There were 4 icons toward the centre,then a speedometer dial looking affair and a digital speed readout and then in the bottom corner nearest driver was the image picked up by the forward facing camera somewhere in the nose of the car.I was only in the car for a short while but found it very distracting indeed when trying to use it just as a mirror!Presumably the icons mean the display can be altered for different info?Whether or not it can be cancelled off entirely I don't know,but how much info do you want your rear view mirror to show?
On the positive side,you can be very proud not only of you parenting skills,but also of him for having achieved this much and hopefully he'll go on to greater things in future