By "Nexus Merchandise Store" what do you mean? If you want to add an actual separate page to act a s a store to buy nexus merch from, i don't think that would be sustainable in the long run, people MIGHT buy at first a few items, just for the novelty of it, but it would die down very quickly, that said, i wouldn't mind having a nexus mug, but that can easily be done in conjunction with some third party service that'll make custom mugs for you, order a limited amount, sell it, then hover the option of maybe releasing a different design later down the line (much later). I don't think an actual store front page would be worth the effort. Not trying to be rude or anything, just being honest.
