You know we are all on the right path here..... however, why does it have to be a basket that adds more permissions at all. I think we are trying way to hard on this one.
Here we go...
A vendors bag, kinda like a carpetbaggers bag. An upgrade to that would be a trunk. These items could have just the one lock or permission, "vendor lock" or "private". Could be made from cloth or leather for the carpetbagger bag or wood and metal for the trunk. Here is a few links for the trunks.
http://en.wikipedia.org/wiki/Trunk_(luggage)
http://www.brettunsvillage.com/trunk.../trunkads.html
This would not add allot of permissions nor would it be a building or stall.
Edit: just thought of something else too.... it would be cool if it worked like a gate too kinda... the open or closed graphic. In "vendor" mode the trunk could be open showing just some generic items, and in private mode its closed. Therefor someone could walk up and see that a trunk or bag or the vendor was open for business. In private mode the trunk or bag appears to be shut or drawd tight at the top such as in the bags case.
What do you guys think?