Kind of off-topic (but not really), but this is the exact reason we went with a TT over a 5er.. No one we knew at the time had a 5er, and we had a very hard time finding a rental truck that was allowed to tow bumper pull trailers. At least with bumper pull, we had lots of options (friends/family).
The problem with rental companies, is they won't garruntee to have that exact truck for you.
2014 Ford F-150 XLT, HD Payload, Max Trailer
2010 K-Z Spree 318BHS