After digging in our heels and grunting through a bunch of Apache rewrite rule combinations, Greg and I came up with a VirtualHost entry for francotoile2.uvic.ca that does the job, in that http://francotoile2.uvic.ca points to http://pear.hcmc.uvic.ca:8081/francotoile/francotoile/index.xql . Getting it to work basically just came down to trying a lot of different combinations of various RewriteRule and JKMount lines until something worked. We gave the VirtualHost stuff to ER at systems who implemented it (and expanded it a bit). Here's the working entry:

<VirtualHost *:80>
  ServerName francotoile2.uvic.ca
  DocumentRoot /home1t/florevid/www
  RewriteEngine On
  RewriteRule  ^/$  /index.xql
  RewriteRule ^(.*)$ /francotoile/francotoile$1 [PT]
  JkMount /francotoile/francotoile/ dev
  JkMount /francotoile/francotoile/* dev
  ErrorLog "|/usr/local/sbin/cronolog
/usr/local/apache2/logs/francotoile.uvic.ca-error_log.%Y%m%d.%X"
  CustomLog "|/usr/local/sbin/cronolog
/usr/local/apache2/logs/francotoile.uvic.ca-access_log.%Y%m%d.%X" combined
</VirtualHost> 

Now we're just waiting on ER to point the Pear site to http://francotoile.uvic.ca instead of francotoile2, which'll wrap up the new version of the site.