Status Update: We have a working port available, with a few more tweaks to be made before it is ready for it's first LKML submital. The source is now in the systemtap cvs server (patches/ia64_support) in the form of a patch series. To view via the web see: http://sources.redhat.com/cgi-bin/cvsweb.cgi/patches/ia64_support/?cvsroot=systemtap
Patch updated for 2.6.12-rc4-mm2, and submitted to LKML: http://lkml.org/lkml/2005/5/17/118
Full ia64 port submitted to LKML, and CVS updated http://lkml.org/lkml/2005/5/23/77
Closing this bug as Kprobes port to IPF is complete and made it into linus kernel version 2.6.13-rc1.