I know this may be early days, but I see mention of chapter negotiations and
this is a somewhat related issue.
Most people here (not in the wider public) know about the Cafepress store
for Wiki merchandise, but it doesn't really cut it anymore. I am aware that
alternatives are being looked at, but this may not be global coverage, and
would likely not cope with localised merchandise for WM UK.
I know the Wikimedia name is covered in the chapters' agreement(s), but if
you wanted to do a members-only T-shirt, could you do "Wikimedia UK,
Supporting the Wikipedia Mission" shirts from a local supplier to keep
shipping costs down? Obviously a cut goes to the WMF, but this seems like a
good point to cover in any future agreement.
Brian.