Yes.  You can use the ProQuest Local Administrator (LAD) to create you own custom login, which you can then add to your library's website.  For more information about LAD please see the Local Administrator Training Guide (PDF format).

To get started, though, here are some custom login URLs for the two major versions of ProQuest Dissertations & Theses (PQDT) database - PQDT A&I and PQDT Full Text.

PQDT - Full Text:  http://proquest.umi.com/login?COPT=REJTPTNiMGYmSU5UPTAmVkVSPTI=

PQDT - A& I:  http://proquest.umi.com/login?COPT=REJTPTNiMTAmSU5UPTAmVkVSPTI=

(Note: If your institution uses a proxy server for authenticating remote users, you may need to add a proxy prefix  to the above login URLS)