Imeo,
I think it should be somewhere in the price range of the GGTB (80€ or 85€ at the very most)!
This is supposed to make people's life easier to get into the TS line, which is your ex-libris but there' still a couple parts you'll need to buy and they ain't "cheap" on their own!
It can't take stacked or big batteries, and in fact the only battery that would take advantage of the Stealth on its own is the IMR 18350 (most protected batts won't draw enough Amps)... And we should also take other mods into account. I mean, the Don for example is a very flexible mod at that price range!
First you'll have to decide wether this mod is supposed to be sold in a larger scale, opening doors to new users, or just a product for a few of them interested in trying the GG's and the current "customers"!
If you choose to produce 500+ complete units then the price must be more low, and you'll end up compensating the profit margin in the other pieces! If you decide to go <300 then you could set a price range more comfortable for you!