The merchant on the square offers storage, not items for sale.
See the Basic Instructions:
viewtopic.php?f=25&t=1374#p8864The Vista graphical bug is certainly very irritating, but it is an understandably low priority. It's on the list and will hopefully be fixed before Beta.
As for our current poverty of graphics, it is a problem, but again, a secondary one. We are always happy to include player-submitted content, particularly graphical content. I believe we have most of our item models (and the ground graphics) from various players. Any time you have something you think would fit in-game or be an improvement on the current model or graphic, just post it on the forums and we'll see if we can use it.
I haven't talked to Karl in a couple days so I'm not sure when today's update will be released, but you can expect it some time this evening.