Heyas Drivin,
That's a tough nut. New PA-44s are spendy...too spendy for the regular guy to buy and put on leaseback. For the same cash, you can get a Columbia or Cirrus, appeal to a much wider rental crowd and have less overhead. You can get away with restricting those birds to "rental only, no training", whereas the 'nole will be ALL training, with the resultant wear and tear.
The number of PA-44s is dwindling overall. Through hard training usage, many are reaching their life limits (14,000 hours on the spar, I think), and they simply aren't being replaced in the same numbers. The relatively few nice PA-44s (and -44Ts, Cougars and BE-76s) are almost all privately owned and are jealously guarded, command insane resale prices, and would never be caught within 100 meters of a rental line.
I'm sure they're out there, but SOFL is a tough rental market...Broward especially.
Nu