Some OT should be allowed here. I understand the need to try to keep the forum mostly on topic, but when people start to self censor themselves, due to fear that a post will be deleted due to it not being on topic enough, that's a bad thing for community!

WIPs should be allowed here. Most definitely. Better products are better for the entire Poser community. There are so many Poser products available from so many different vendors, I find it silly that any particular site would be concerned about WIP posts for items sold elsewhere.

It probably is counterproductive from a business stand point to ban WIPs as well, even if the item ends up being sold elsewhere. How so? There are a lot of popular products sold here that are texture sets or add-ons for products sold elsewhere. Being involved in the WIP process here for an item will encourage developers here to make add-ons for those products and sell them here. This is not only good because of the revenue from those items, but it helps establish in the minds of customers that Renderosity is a good place to go for add-ons for all products, even those bought elsewhere.

Of course, as others have pointed out, banning WIPs also drives away vendors who may have otherwise sold items here. That alone should be reason enough for a quick reversal and it would probably be productive to make a very public announcement on that change of policy.

Encouraging WIPs = Good business sense.
Banning WIPS = Bad business sense.

May seem counter-intuitive in the "Us vs. Them" mentality, but encouraging an open WIP process here will actually draw more products and revenue here.