The most details I've seen are here:
http://pages.ebay.com/sellerinformation/news/FeeUpdate2010.html

"Make sure your Store Inventory Format listings have been reviewed, edited as needed, and ready to become Fixed Price listings in core search results. Continue to liquidate any listings you don't want to continue. All Store Inventory Format listings will become Fixed Price listings and automatically renew at the new rates starting March 30."

There will be no store inventory format at all. Stores will become a subscription that (1) reduces the cost of fixed price listings, and (2) gives sellers the ability to organize their listings into custom categories with custom storefront pages.

So I'm not really sure how aw2k will be impacted. A regular ebay profile will work for all listings - and if you have a store, you'll have the added ability to put items into store categories - which already exists in aw2k ebay profiles. So probably no reason to even have "ebay store" profile types at all - in fact, they probably won't work after 3/30 anyway.

I upgraded my store to a premium after I worked the numbers. I was already running a good number of fixed (at .35), plus store at .03. By upgrading to the $50/month store, my total listing fees for everything I list now will only increase slightly - and give me all my items as core fixed priced listings. Not a bad deal at all for the extra exposure.

Just about all my listings are GTC - both fixed price and store - and you can't change the durations in either format. For store GTC, you can end them in "bulk", but fixed still need to be ended individually.

The most dangerous situation is someone with many GTC store inventory listings, with a basic store, that might not realize that every one of their listings will be "upgraded" to fixed price and will automatically renew at .20 each. For 1,000 listings, their monthly listings will go from $30 to $200.

Based on everything I've read (be sure to check out all the links on the URL), after 3/30 there is just auctions and fixed price. So something is going to change in the API for aw2k.

My biggest concern is that if I have 200 GTC store items suddenly become GTC fixed price items, how will aw2k see them? Will they still be accessible as "store" inventory during updates? Will the "bleed over" into my regular ebay profile and get grouped with my regular fixed priced profile? All things I don't want to test...LOL.

My plan is to have as many items as possible already as fixed price (using this wonderful .10 sale), and on 3/29, I will kill all of my remaining store inventory items - which can be done in bulk very easily on the ebay side.

I then move anything I still want to list from my aw2k store profiles to regular ebay profiles, and relist as fixed price as needed.

I think this will avoid any aw2k complications.