I've found it hard to find a 'good' insurance carrier who will insure them simply because there are college students living there.  

This will be a fight amongst the attorneys and insurance carriers.

Most major renter’s insurance carriers have policies that will have at least the basics covered, but definitely have your tenant get a few different quotes and do some cross-product analysis.

Ross Diversified is another insurance carrier I use.

My agent proceeded to tell me that there are no policies out there that cover this type of situation outside of a special policy from a non-standard carrier like Lloyds of London.

@Keith Torres For all practical purposes, Renters insurance is required by most insurance carriers. 

Also to increase from a couple million to a 10 million coverage is not super expensive; i.e. the coverage costs are not linear.The insurance carrier that most of our RE assets are insured with would not provide us an umbrella coverage (deemed us too risky) so we had to go with another carrier (a carrier that did have a couple of our properties insured with so not a completely new carrier, just not our preferred carrier).I suspect that the reason you do not see these in any of the calculators is that it is not linear per property. 

The first insurance carrier I found to not have a breed exclusion on small residential policies was surprisingly State Farm.

This morning, leaving for work, I left a note for my Postal Carrier.

If you have enough locations I would suggest buying one general liability policy with a $1,000,000 limit from a private carrier for all your properties and one property policy for all your locations (if possible and affordable).