I've been looking for the 1956 Bel Air and all I've found was the Revell Del Ray kit and the Monogram Bel Air Classic Cruiser edition. Like Snake45 indicated, there's a big difference between the two. The Del Ray has a large B-pillar, and the door is shorter.
As for the Classic Cruiser, It's a hopped up street rod version so if you don't want their canned look you will have to kit bash both. I'm going resto-mod and basically scrapping the stock suspension etc. anyway so its no biggie for me.
I was born in '56 and I'm building a Ford, Chevy, and Chrysler from that year, and believe me the choices are limited!