Although I'm no mod_rewrite expert, I'm a bit confused (and maybe you need to give a little more detail on what the original ezproxy urls look like), but it seems to me that if all you're trying to do is redirect http(s)://ezproxy.switchinc.org urls to a new domain, something like this should suffice:

RewriteEngine On
RewriteCond %{SERVER_NAME} ^ezproxy.switchinc.org$ [NC]
RewriteRule ^(.*)$ http://0-topcat.switchinc.org/$1 [R=307,L,QSA]      (sub R=301 if this is a permanent redirect)



If there are numbers/chars preceding the 'ezproxy' portion (e.g., 1-ezproxy.switching.org), you'll need to show us some example urls and note whether all are in the same format (e.g., can we expect the same number of dashes prefixing every url? or that all prefixes are numeric?).

--
Mark Vega
Programmer/Analyst
University of California, Irvine Libraries - Web Services
--