I use two or three cards, five or six times a day, always within ten feet and in the sameish direction of my car.
I would like to add a transponder to my vehicle that knows where it is via GPS or wifi presence, and has a "send" button perhaps in my phone to transmit the appropriate RFID card so i don't have to fuddle with it by hand through an open window.
I've also got one card that I've tried keeping in my visor and it's been deforming in the heat under the pressure of the clip that holds it!
My wallet is also utterly exploding, so reducing a couple millimeters of bloat would help. Not to mention i have problems reading them without taking out of the wallet if the reader picks up two at the same time.
It looks like getting an antenna to work at that distance might be a bit of a challenge but that the rdv4 kit includes emulation which is the holy grail of what i need i think. I'm thinking of buying the proxmark 3 rdv4 kit.
I guess what I'm trying to accomplish is Android Pay for RFID cards.