You really need to look around and see if you can find an old-timer to paint your doors. It's really not as expensive as you think and if you let him design it the way he would of in the 50s he might cut you a nice deal in exchange for the fun of bringing back memories.
Most guys in the biz that have been around that long now own or manage sign shops and I found them anxious to do the job.
It's worth a shot... vinyl is pretty thick to be trying to feather the edge with clear plus you run the chance of having some reaction between the clear, vinyl and adhesive.
