Can CiviCRM set up an event registration on a separate server?
CiviCRM profiles still have HTML snippets, which you can post on another website. They can be used for Mailing subscription forms, but if I'm right not for event subscription.

Other options I am thinking about would be:


2 sites, 1 CiviCRM
http://wiki.civicrm.org/confluence/display/CRMDOC/Multi+Site+Installation
So you are using CiviCRM with 2nd site, and only form submission via site 1
Creating your own form on the front end site and connect with CiviCRM via the CiviCRM API