You have a few options...
1. A Zenith made for a GMC (you should talk to the other Jon...CarbKing about this scheme) I'd suggest one made for the 248, but he may have other ideas.
2. Rochester B
3. Carter 3211s with a manual choke adapter (the ones available today are sort of cheesy Chinese looking things and several outfits sell them...Dorman for one)

You could use a Carter 2100s (made for the 1953-1956 235 and not easy to find one which hasn't been ruined by the rebuilders). As you know there were some differences between the 53-56 235 models and those made between 57 and 62. The 3211s recognized those differences and the 2100s was engineered before those changes happened. Hundreds of thousands of electrons have been spent discussing the differences between Rochester and Carter here.

Zenith carburetors are good, but a new one is going to be very expensive (last time I looked over $1000) and a rebuilt one isn't going to be cheap either...and spending that much $$$ you need to check out the rebuilder very carefully. I won't mention names but there are some I wouldn't touch with a 10 ft pole. I have 3 New Old Stock Carter 3211s models listed here...one is spoken for and I've had nibbles on another of them. I've gone through these, cleaned and replaced gaskets, checked all parts, etc but it is devilish hard to find new Carter carburetors today. Good luck.

~ Jon
1952 1/2 ton with 1959 235 | T5 with 3.07 rear end