That is a great story, thank you. And it looks like you have a very nice cooking space ready for the MT.
What to buy? I can't tell you - because I don't know what you cook. A Slow N Sear makes it very convenient to cook a low temp, then finish with a high temp. A 26er is BIG, which is nice. It depends on what you do with it. (Hey, maybe a rotisserie?)
WNC's suggestion of going vintage sounds good to me, but I don't know what you prefer.