I recently bought (on e-Bay) a 400mm/5.6 ED (non-IF, K type) in LN condition. Initially destined for the Df it performs great on the D800 too.
Finally it features a wide and solid tripod mount
I couldn't be happier.
Excellent find. If you don't mind me asking, what did you end up paying for one of these?
My second copy that I just got last week was for a ridiculously low price as I don't think that the shop I bought it from had any idea as to what they had on their hands other than "an old manual focus Nikkor"
I paid ~$850 US for my LN copy a few years ago from KEH, which appears to be what KEH wants for the ED-IF version now (which is waaay too much IMHO).
John