Despite your "Debbie Downer", realistic view of things trying to squish my dreams, I will continue to hope that they find a way to release the rings separately, because I really don't like the idea (whether practical for Hasbro or not) of rebuying all the JSFs just to get the rings.
I too am not relishing the idea that I might be having to re-buy all of the JSFs only "this time with rings!"
However, the reality is that Hasbro spent a good amount of money sculpting and tooling the Hyperspace Ring, so they are going to use it more than just this one time.
The sensible thing would be for them to come out with one more new design (such as Aayla Secura's JSF) and include the Hyperspace ring with that as an exclusive to either TRU or Target. Then on top of that offer JUST the hyperspace rings for Plo Koon's, Kit Fisto's and Saesee Tiin's JSFs as an online exclusive with HasbroToyShop.com.
A two-pronged strategy like that would increase the ROI on the Hyperspace Ring development. I also think a lot of collectors who already have those three JSFs would be more open to the idea of just buying three Hyperspace Rings as opposed to re-buying the vehicle.
I don't have a lot of faith that Hasbro would be so kind though - so I'm kinda expecting a re-release of the Plo Koon JSF w/a Hyperspace Ring, exclusive to Target at some point in 2008, perhaps even as a Clone Wars line exclusive.