Just the thought of the Chicago Stadium organ getting a second life in Las Vegas makes me smile
Five manuals/keyboards? Don't know if the top two will get much use. (Most organs have three. Many have to get a real long-armed organist
)
Do you know how many ranks? (Sets of pipes to make up a "tonal set")
(IIRC, a "simple" church pipe organ starts in the mid/high six digits. Guessing a "new" large -- to fill space with sound -- organ would easily run ~$1m for electronic, and perhaps $2-3m for a pipe organ. And given the complexity, I can easily see it costing another $1m+ just to install the organ, much less disassemble from the Maloof estate, transport and then (re-)install.)
Given the age, I'd guess there would be at least one full time tech needed to service organ.
Also, given the extreme temperatures in Nevada, and the history of temperature fluctuations of pipe organs (if the sun is shining on one side of a church, those pipes are warmer than the side in shadow, and split ranks can be out of tune due to the difference in temperature), they probably want to install all the pipes on the "same side" of the new arena.
Wonder if they might install some Wurlitzer "enhancements" (drums, percussion, etc.). Wurlitzer organs were the type installed in many movie palaces in the early century to accompany the silent films, and had literally many bells and whistles to add to the organ sounds at the organist's beck and call (with just one flick of a switch/stop).