Where can I find a stoat?

you will not find a stoat in a box naturally. You will either have to lure it there yourself or pay someone to do it for you. Or volunteer to help a grad student do a stoat study and then maybe they can show you how to place a box in just the right way, with all the right stuff in it (think chicken) so the stoat will volunteer to go into the box.

Do not confuse going into the box willingly with staying in the box happily.

Good luck, if you want a stoat in a box, I am afraid it is going to take some effort on your part. However, if you want a photo of a stoat in a box, here is a nice link:

http://www.learnz.co.nz/daily.asp?id=106

A stoat is a member of the weasel family from eurasia.

Stoat

Distribution: widespread throughout the British Isles. Also throughout the rest of northern Europe, the tundra and temperate forest regions of Asia and North America. Not found in any Mediterranean regions.

Habitat: woods, farmland, uplands, moorlands, marshes, sand dunes and hedgerows