I have three suggestions, keeping in mind durability, looks, ease of use, price and size of containers...
1) Hi-Temp Terminator Polymer Sealant- this has great durability, the looks are up there with the more expensive and boutique sealants, and is available in gallon containers. with a phone call to TOL, I think you can even get larger containers (5 and potentially 55 gallon drums). Buffing off dry, Terminator can be tougher than most to buff off. However, if you use a QD (Aquawax, OCW, or ONRW- my favorite) it comes off extremely easy. The whole process is a BREEZE when applied with a PC and buffed off with a little ONRW QD. (its my favorite, if you couldnt tell) Gallon= $26 (
http://www.topoftheline.com/16ozmaxpains.html)
2) Mequiars #26 Hi-tech liquid yellow wax- You mentioned the look of a carnauba... it has it. I got away from this wax in favor of other "newer/better" waxes (CG for example). But now I am back and much happier with the results. Using a PC for application, it goes on like butter and buffs off like butter. I dont have a price on it, but I know it can be bought in gallon form.
3) TOL Express Wax- *I have not used it* However, according to their website, it could be just the thing you are looking for! And, at 22.95 a gallon (2 gallons for $42), the price cant be beat! I actually have some on order so i'll let you know how it works out for me. (
http://www.topoftheline.com/exdetclean.html)
Hopefully one of these mentioned or the others mentioned will suit your needs. Good luck.