I have a house very close to the Cleveland Clinic that I am thinking of doing this for extra cash flow.

Signed up to Cleveland Clinic's internal housing office last year and paid the $300 fee per property for the year - did 3 properties. 

I'm sure you can find decent pockets in Mesa or Tempe, but it won't be as easy as in the West valley.As far as areas go, the safest answer is anywhere near a Mayo Clinic.

Tax Adviser has a great read on the topic, linked below, fairly technical, but gives you an idea that it may not be as black and white.https://www.thetaxadviser.com/issues/2012/aug/clinic-story-0...

I posted a series of comments in this Bigger Pockets feedhttps://www.biggerpockets.com/forums/925/topics/1164202-folsom-could-see-over-500-000-square-feet-of-new-doctor-s-offices-and-medical-clinics

From what I've heard, the people who are coming to Cleveland Clinic as travel nurses have their housing figured out for them and the people you'd have to get with to get into their program are very hard to reach.

(New carpets, Siding, Paint, maybe just a few appliances) The reason being is that many (many) people seem to forget that rental housing is incredibly hard to come by in small towns or outskirts of cities where the primary industries are medical clinics, restaurants, bars, farms, and factories.

His wife works three days a week in a vet clinic -- not because she has to, but because she wants to. 

I do know that Cleveland is enjoying an economic revival based on healthcare (Cleveland clinic regional hub), but long-term, I don't know what that will translate into population-wise. 

Jeremy, you are doing what I wanted to do when I was stationed @ NATTC Branch Clinic as the LPO (USN).