A few updates and clarifications:
Lens pro to go: appears to carry a 645z and a few lenses.
Rent Cameras, Lenses, and Video Gear ? LensProToGo
Camera lens rentals has changed their website. They also do not offer any camera/lens gear except for Nikon, Canon, and Sony. New site is:
Rent Lenses, Cameras, and Drones ? Camera Lens Rentals
Borrow lenses has no Pentax gear as far as I can tell. They list a DFA 70-200 but it’s not available with no future availability that I can see. No used gear for Pentax in my search came up either.
Lens giant: no Pentax gear.
LensGiant - Nikon and Canon dSLR Camera and Lens Rentals Sony, Nikon, Canon only.
Samy’s, Adorama, and others all appear to only rent locally. These two rent primarily to professionals and Adorama requires proof of insurance specific to the job/rental.
In Bozeman MT and Jackson WY you can pickup gear from local shops but none appear to carry Pentax gear at all.
Essentially it appears lensrentals is Nearly the only game in town for renting Pentax gear by Mail. They carry 51 items, including batteries and an AC adapter, 13 items are 645z related (body and 12 lenses) they carry the k1 mk II and the 645z and the K3iii.
Adorama