AS you know Martin I would offer. ( when working) an Allison at retail at about what you have stated ..
but when it came to the deal 9k was closer to the purchase price, As you know these OEM have got some lesson to learn on option pricing, as all are very closely linked to demand. I paid 1500 Euros for mine and fitted myself with Allison assistance. Every MAN fire engine in the country I supplied, most have Allison.
Your 9 speed ZF is an amazing box, But the option price is massaged by the OEM.
On our first ever overnighter in our motorhome last year, I got into conversation with a chap who had one of those aircraft carrier sized motorhomes with the sticky-out bits you can crank out at the sides. He was bemoaning the fact that he had planned on attending Carfest but had been turned away on the basis that his mobile mansion was too big. Presumably size is important, particularly in the UK where we do have corners on the roads and some of the roads are only two lanes, but if it's what floats your boat, good luck