Short B,
these are the stock style that is discussed in the thread linked in Cap-n-cray's post. The issue is that for the 3rd gen trucks, you have the option of manual or power in this style. For those of us with the 2nd gen trucks, the only factory option is the mirror in your ebay link. I had factory power, but non flip out on my truck. I wanted the towing flip out mirrors and still keep power mirrors so I did the swap.
To answer Paveman's question as to why people are wanting this style of mirror, for me I like when the mirror is flipped out in tow mode. It is taller rather than wider and allows me to see the tires on my trailer while still having enough mirror area so I can see traffic behind me. I drove transit school busses for years and they always have tall mirrors rather than wide mirrors and it boils down to preference. Another benefit is that from the outside, you can't tell my 95 from a 2002 truck with the factory mirrors. Also, I didn't like the elephant ear style of some of the aftermarket mirrors.