Awesome.
[EDIT] I've just re-read the original post again and realised that this has already been covered, so this post is a bit redundant.
oh, so parallel headers is out already? too bad. the mechanical/dimensional compatibility thing apart, i fail to see to advantage of an onboard SD card. even if i need one, there's so many cases where i'd like the SD card to be somewhere else physically so it can protrude from the panel / casing / whatever; that may be a horizontal socket or it may be vertical. that may just be me .. but it's always easier to add stuff than having to cope with things that aren't essential.
or was that ("already covered") re castellated?