I've heard conflicting things, that HD-DVD has no region coding, and also that it there is region coding but that it has much bigger regions. FWIW, the HD-A1 manual does not mention region coding at all, a point about which the 1st generation DVD players were all very clear on.
Right, SD DVDs are still region coded and the HD-A1 is coded R1. BD players presumably will work the same way, since they're still both subject to the DVD Forum rules as far as how they handle SD DVD.