Looking for suggestions for an internet content filtering appliance

["Frank Bulk - iName.com" <frnkblk () iname com>]

We offer an optional internet content filtering service to our residential
and business customers using M86's appliance
(http://www.m86security.com/products/web_security/m86-web-filtering-reportin
g-suite.asp).  

I've been in conversation with them since Q1 regards IPv6 support, but the
update I received today was that IPv6 support won't be available until
middle to late next year.  That's not ideal, because the local college is a
significant user and they started with IPv6 this summer.  College students
can easily bypass content filtering by using the IPv6 version of the site
(i.e. http://www.playboy.com.sixxs.org)

Wondering if anyone can point me to a similar appliance.  I know that
Barracuda has such an appliance but it has one limitation I don't like, and
that Fortinet and Ironport have more expensive products.

It must be able to operate in pass-by/SPAN mode, not inline, and handle
traffic rates up to 1 Gbps.  We currently move 400+ Mbps "by" it and
internet usage only goes up.

Thanks in advance for any suggestions you have.

Kind regards,

Frank