I've actually cleared things up a bit with google and found an interesting Taco Bell testimonial. This page has a lot of info.
Among other things, it claims:
- The whole bit about guns are caulking guns, and that's for the sour cream and guacamole, not beans.
- The beans apparent come as a dried powder and are reconstituted.
- Ditto for most of the sauces.
- Meat and nacho cheese come in pre-portioned boil-in-bags.
- Lettuce arrived at the store pre-shredded
- Tomatoes were peeled and sliced on-site.
Mind you, this one person was talking about when they were 16, and they don't say how old they are now.

Interesting details, and as I'd figured, they certainly did change their bean procedure. I was surprised that it's a powder, and not a canned bean product, but I'm sure they did analyses to determine what would be most cost effective, and produce the best tasting product, within reason.
When we used to make the beans, and this was 21 years ago, I thought the weirdest thing about it was that, after cooking the pot of beans, we'd whip them with a rotary beater attached to the end of a power drill. "Drilling" the beans was actually really tiresome, so employees bigger and older than I usually did that.
Both beans and meat were cooked in huge pans, meant to hold 40 pounds of product, each. For the beans, this was the second "frying," and for the hamburger, raw meat was cooked with the seasoning this way, and we used large rakes that looked like oversized potato mashers.
We did chop tomatoes with a wall slicer, and there were grates of different sizes for onions and tomatoes. Cheese was shredded in house, and we fried all the taco and taco salad shells, the pizza shells, and they had a fried flour taco shell at that time, too. They usually didn't make me do fryer detail, as they made male employees do it instead. I'm not sure why, because other fast food chains didn't distinguish between whether it was a male or female working the fryer.
Nacho cheese and guacamole came in cans. I'm not keen on the canned guacamole, and I don't think many other folks were at that time. We didn't put the guac in guns, because I don't think we sold that much of it, but we went through 8 or 9 cartridges of sour cream on a shift.
That pretty much covers everything that I know about the Bell. I have absolutely no idea why I wrote this, by the way, as I'm sure no one could possibly find it interesting.