TRANSPONDERS

With winter just about upon us, the snowbirds are preparing for their annual migration back to C.V. Last year there was some discussion concerning the possibility of a "portable" transponder that could be utilized by snowbirds who rent vehicles or do not wish to put them in their vehicles permanently. Has the issue been explored?
As was previously discussed, while there can be some potential abuses with such a system, the same can be true with permanently installed devices. I believe if abuse does occur, it is an enforcement matter, not an issuing problem.
As we all have witnessed, the gates during the winter months, during peak hours, are often backed up. The issuance of transponders to responsible unit owners can alleviate the wait time to enter.
In the event this technology is not currently available, what is the process for getting a transponder and how long does the process take from ordering to installation?