I'm finding them by doing a search for them, but I'm assuming they are pretty much a standard size. Based on what I read, I don't think reflectors and flags replace the sign though, sounds like it's actually the law. I have reflectors on my cart as well...little stick on reflectors. Only thing I read as an exception is if your "religious beliefs" prevent you from using the sign. But it specifically said horse drawn vehicles needed the sign too.
I just have a little easy entry cart, and guess I may have to just figure out how to place a big sign on it....I thought they might make smaller ones too but I'm not finding them. I'm seeing two types, stick on and the kind with holes. There's really nowhere to stick one on, so I suppose I could use zip ties or something and get one with holes.... unless someone jumps in with a better idea!
I took our mini and cart trick or treating with my son last year and we had a BLAST! I did use a friend's sign for that, and used zip ties to hold it in place...it worked ok for that. I also had lights and glow sticks dangling from the horse, and the cart....
Angie