Basically, the problem the vendor has when selling a product with a large appeal is that they want to sell it at the highest price the buyer will bear. If portion A of the buyers budgeted $100, and portion B of the buyers budgeted $150 for your gizmo, how do you price your gizmo to extract maximum value from the buyers from A and B? If you sell it for $150, A won't buy. If you sell for $100, you're missing out on $50 from B.
The solution is to make minor modifications to your product to sell the Basic version to A for $100, and the Premium version to B for $150. If you've done your manufacturing right, the cost of one over the other is minimal, and you're getting the maximum value from both portions of buyers-- I mean market segments. :)
[1] http://en.wikipedia.org/wiki/Market_segmentation
And to expand on your your issue with the availability of 16GB models... you represent a small enough niche at this stage that it's not worth Lenovo's effort to design and source parts to accomodate your segment.