Seems like there are two questions here, one about avoiding a glycol set up, the other carbonating 1BBl of beer.
For keeping everything cold, depending on how much beer you have at once, you can build a cheapo walk in cooler with a window A/C and a coolbot.
Using freezers with temp control units may be cheaper than that, but it depends on the total beer volume you want to keep cold at one time and some other factors.
If you are using 1/2 BBL Sanke kegs, lifting them up and then bending over to lower them in to a freezer is going to get old pretty fast. Maybe some kind of a hoist system? If you have a walk in, you can use a hand truck to wheel the kegs in. You can put your taps right through the wall of the walk in and have the storage and serving kegs all in one place.
Sanke kegs also have their own challenges when it comes to cleaning them.
A buddy of mine has a side business auctioning used restaurant equipment. Used commercial walk in units come up for sale all the time, and some go pretty cheap. You usually have to go to the restaurant and disassemble and get it out of there and there's usually a deadline. Note that some run on 3-phase power, some don't, so you have to look at that if you go that route.
Do you really need to carbonate 1BBL of beer at a time? As others have said, why not just transfer the beer to corny kegs and carb up 2 at a time as you need them?
As the kegs get kicked, you can have them to refill with the next batch, compared to having a 1BBL or 1/2 BBL brite tank sitting there practically empty.
I've seen some 10 gallon brite tanks for about $500, Sabco has 1/2 BBL Brite tanks for $380. Three 5 gallon corny kegs used would be like $150?