Ran accross a great article on how to use SxS Manifest files to intsall COM objects as Non-Admin.  This approach has several limitations

  1. Only works an XP SP1 (and higher) and W2K3 (and higher). 
  2. Requires you to have write access to the directory containing the executable
  3. Doesn't allow you to just register COM objects for all apps

However this is a handy piece of knowledge to have. 

http://www.red-gate.com/other/com_without_registration.htm

It is in fact possible to register COM objects for all your apps as an LUA.  I will hopefully blog on that process sometime this week.