Webconverger 2.36 has support for the
http_proxy= boot parameter. Conducted some basic testing, though I have not tested SSL.
I was thinking of using Firefox's network.proxy.autoconfig_url feature, though it didn't seem to work.
Webconverger's kiosk (>>6.21) extension now quits on F10 or when the user closes the last tab. This took a lot longer than expected. Thanks to Jamie for helping me out on this and all the helpful people on IRC.
I am looking for a new home for webconverger.org. Looking for a nice VPS vserver/xen solution in Europe with Debian of course.