The 3 I would use would be the Boley, models. The Spartan has a high side body on one side. The ladder version actually wil make a nice rescue pump with some mods. Lastly the GMC/Seagrave has what I believe is the basis for RD's rescue pumper for the body. It has roll ups on both sides.
I assume you are looking for high sides on both sides of the body. If so, you are short on luck. You could look at modifying the Boley heavy rescues by cutting the tops off and building the hose load. I have used the Matchbox Mack rescue to do.
If you want to pay a handsome sum, then you can look to the German models.