I'm gonna agree with esp47 on that one. My car had the same problem, worn out upholstery at the driver area, some broken springs, and deteriorated foam. My first thought was to replace it with a couple buckets. The ones I found were from a 69 Mustang. Looked like it would be fairly simple to adapt them with little modification. I was wrong. Floorboards are not flat, nor symmetrical, so brackets to match the early Mustang was not going to be that simple.
I decided to re-think the idea. Got in touch with SMS < I think that was the name... They claim to be the worlds largest supplier of OEM auto fabrics. Sent them my vin number info, they sent me an exact match of 42 year old vinyl. Impressive. I took the bench to my local upholstery shop, they put in a couple new springs, a layer of 1/2 inch foam over the top of the original foam, and recovered it all in the original two tone colors. Looks just like the rest of the interior, which is in excellent condition.
I'm into it around $600, maybe a little more, but I am very happy with the results, and I am happy to have a full bench seat... My li'l wifey is happy with it too. Somebody already made mention of this in another thread, but bench seats are pretty darn hard to find in any cars nowadays. I kinda think bench seats are the new 'cool' seats for a weekend cruiser.
As far as a floor shifter, that is still an option with a bench. I know there are lots of cars with this combo, and that is what I plan on doing myself.
I'll try to get a picture later