I thought most (if not all) gigabit Ethernet implementations auto-detect host-to-host connections and handle the crossover for you.

They all do now, but it's still an optional element of the standard.

It was optional in 100Mbit. In gigabit, it is mandatory.

"Automatic MDI/MDI-X Configuration is intended to eliminate the need for crossover cables between simi-lar devices. Implementation of an automatic MDI/MDI-X configuration is optional for 1000BASE-T devices. The assignment of pin-outs for a 1000BASE-T crossover function cable is shown in Table 40-12 in 40.8."

Here's a link that does not require IEEEXplore access: http://www.scribd.com/doc/46141801/802-3ab-1999

I say, I stand corrected. I was sure I read the opposite somewhere, but I would not dream of contesting your reference.

They do. Maybe he meant 100BASE-T4.