SC,
The only one I know of is this one:
http://www.tnttt.com/viewtopic.php?f=55&t=49879
It's not exactly a wild goose, but it is the closest I can recall.
In case you aren't aware of it - I didn't realize they were there until someone pointed them out to me - at the top of the page under "Design Resources", then "Vintage Trailer Plans", there is an article on a Wild Goose. It shows some pictures and has plan dimensions.
There are a few Winter Warrior builds on the forum. These are similar to the Wild Goose, but have hard sides instead of the canvas sides.
Take care,
Tom