I remember the Venetian used to have them some years back, but I was unable to get confirmation on the phone they still do.
got some visitors coming soon and mobility issues and getting around the hotel are a consideration for where I would tell them to stay.
Pretty much any hotel on/near the strip would be fine, they are more about accommodation than specific location.
Anyone have any insight? Thanks in advance!
...not too expensive.
https://totalrewards.custhelp.com/app/answers/detail/a_id/380/~/flamingo-las-vegas---wheelchair-rental
Hi Doc! 
The following casino resorts (listed below) have a contract with a company who supplies hotel guests with electric wheelchairs.
After making a room reservation at the hotel, call the company 'Desert Medical' (866)711-9171, to rent the electric wheelchair. When the guest arrives, it will be waiting for them at the Bell Desk.
Electric Wheelchair Costs:
$40 - 1 day / 24 hours
$70 - 2 days
$105 - 3-4 days
$120 - 5-7 days
Hotels With Electric Wheelchairs, Available Only via 'Desert Medical':
Mirage
Bellagio
Aria
Vdara
Monte Carlo
New York New York
Excalibur
Mandalay Bay
Luxor
MGM
Doc, I hope this info helps, and your guests have a delightful stay in Las Vegas