The video above is good, I liked it too. The breakers are much less and it may be satisfactory for many applications, but I am still a bit worried about the modern electronic engines (personal opinion, no experience here).
Personally, I am sold on either the PH-180s or PSX-ACs (or both). (There is also a PSX1,2,3,4 for DC). But those are probably the $$$ ones you speak of (DC versions are several dollars less than the AC versions). Tony's Train Exchange has all models of the PSXs and Charles Ro has the PSX-AC. Pricing at both places is comparable. Maybe they would offer an additional discount for the quantity you need here?
Also, there have been some discussions here about magnetic breakers which I believe are supposed to also be pretty fast, but I have had no experience with any of these. I believe these are priced about midway between the current sensing breakers and the PSX models. Might be worth doing a search for them and see what turns up. It's been a while since I have seen them mentioned here and I can't recall any specific threads or posters on them or I would offer up a link for you. Pretty sure some here are using them though.
The older Lionel #91 breakers as said to be very fast as well (no personal experience here either), but have not been made in quite a while. It might be problematic in finding the quantities you need although they do show up on ebay fairly frequently. I also don't know if they are DC compatible?
Maybe GRJ, Stan or one of the others here that are more knowledgeable on the magnetic breakers will be by to add more about them.
Good luck and let please us know what you end up with. I am always interested in this stuff and the circuit breaker questions come up quite often around here.
