Had some recent wins from the States quite quickly, may be wrong but thinking first in last out regarding backlog.
Rather than rotation depending on date. Similar happened last year if I recall.
Last year ALL turned up in the end, it's the not knowing on the expensive / elusive stuff that hurts.
One from 01/12/10 has recently arrived from U.S.A. whereas I'm still waiting for one from 26/11/10 from a reputable dealer in the States.