As suggested, ask Ken / the admin.
Personally, I'd think listing a link to store in Trading and Sell forum would be fine, given past precendent. Having said that, a single thread would quickly roll off the page and would never be seen again. Is that the best thing to do? People would quickly get annoyed if you posted weekly to thread to say nothing more than 'I'm still here' or some such just to move thread to first page again. Not being a bear person, I never really cared for Erin's threads, though did click on the single auction link once in a while. With a store... its not like you should post a different thread for each item in store.
One thing a little more "in your face" is to add a link to store in your Profile, kinda like the Winzy thing I have. As you post frequently enough, would probably get folks to click on it to see what's up there.
Can also advertise on the site via banner ads. Might get a good deal...
Not knowing what your store is for, I'd question if people here would be interested or if some other place would be better. You've been around here long enough to judge that.
Good luck.