I have seen those trolleys use can use to pull erected crates but can you get anything that you can slide under the folded crate as an alternative to carrying it folded?

I would imagine that this is far easier to navigate through the show than a huge erected one.

Has anyone seen something like this?

Yes, I've got one, got it from Homebase DIY store for only £24.00. It folds completely flat, wheels fold in to it also. Just pull the handle up, press a button, and it's ready to take the cage (tied on with bungy ropes, it comes supplied with one, but found it to be safer with two). It's really handy for shows when the venues quite a way from the carpark.

Kay (Kayanarra)
Bearded Collies