Auto body repair & detailing: floor pans, wire feed welder, j c whitney

Question
What is the best way to replace a rotten floor pan when you are unable to find an aftermarket part? i have a 81 monte carlo that is suffering from a drivers side floor pan that is roughly 2 by 1 foot that is rotten. there is some good areas in it, but if i ground at that surface rust I am sure id see day light in no time. i spent all day at a wrecking yard finding a replacement and cutting it out, only to find that after wire wheeling the pan the damage was far more extensive then originally thought. i have a low quality wire feed welder, and a rivet gun at my disposal with all the common hand tools. the car is a rare option, but no longer numbers matching. i would like too have the worst hidden by carpet, and least shown under the car.  

Answer
Have you tried Year One or another source?They have all sorts of different restoration parts for many models.Another suggestion would be to use a replacement floor from a similar type of car or year.Since you have a welder your options are endless with a little patience.Eastwood restoration has bead rollers to make your own panels but they are kind of pricey for one job.A little creativity and you will have a new floor in no time.Also J.C. Whitney has some good generic sheet metal parts too.