Re: Tracker Hidden Information
Yes you can for sure in 1.10 version (there is the option to set a field as visible or editable only by admin, for instance.
You can try also in 1.9 with the earlier feature of hidden field (viewable and editable by admin or users, I think).
Search the doc. for trackers information:
http://doc.tikiwiki.org/Trackers
(ip address is a field that you can add, already, according to doc.tw.o)
HTH