To my knowledge CUPS is the only spooling system available for Unix
which speaks IPP even though Patrick Powell who developed LPRng was
one of original IPP developers as well. LPRng should have been able to
work as IPP gateway as of 4.0 but there is no LPRng 4.0 and Patrick
has abandoned LPRng around 2005. I am not really sure if LPRng can
speak IPP.
I know very little about Windows but I would swear
that I have seen or read that Windows can speak LPD printing protocol.
I also have no knowledge of Samba but I would swear that I read
somewhere that supports LPD.
Best,
Predrag