In the episode Ariel, the crew needs to disguise themselves as medics in an ambulance to help Simon and River get into a hospital.
More after the break...
Some more screencaps featuring Jayne:
Zoe, Mal, and Jayne:
A few years ago, a group found the ambulance prop in the desert and decided to give it a home. I don't know what ever became of it, but I know they took it to some conventions.
And also, I can't remember where I got this image, but I swear someone did a line of patches and this is a picture of it. But, I could be wrong and this is an actual picture of one of the screen-used patches. I really should have done this blog years ago.
My Photobucket Album.