smallest auto FP flash for Nikon

I'm looking for a smaller, more portable alternative to my SB900 for wide-open, sunny, fill flash scenarios like in this shot:

1/1000 F1.4

My understanding is that the SB400 can't do auto FP shots at high shutter speeds (1/1000+), but maybe this is wrong. Can the SB400 do this? Or are there other smaller flashguns that will? Thanks in advance,

Mike