I should have engaged the brain before I started typing.

What I should have said is that some electronics manufacturers APPEAR TO make a specials model for places like WalMart. I have no proof that such a thing goes on. You may be totally right about it being rare; I used much broader language than I should have. (I'll blame solar flares, bad mood, off brand coffee...)
A few years ago while shopping for televisions the wife was telling me about great prices at WalMart. I took a brief look at the sets she had mentioned and found model numbers at WalMart that weren't for sale through any other outlet that I could find. The models for sale at WalMart invariably had significant compromises in performance to the normal product line items with similar model numbers.
In the case of an HDTV, using a cheaper, trailing edge panel in the same enclosure than a more expensive panel is put in for sales through other retailers yields a price advantage to the discount stores.
Obviously there is nothing wrong with making a cheaper model to sell through discount stores. The only issue I had with WalMart was that the model numbers, packaging, etc SEEMED (IMO) to be conveniently misleading to consumers.
(I hope this post is readable. It's been a long night and I'm a bit punchy. Forgive me if it rambles a bit.)