Looking for freebsd/openbsd Open Source project for multi-WAN load-sharing/failover firewall/internet gateway

[Sanjay Arora]

I am looking for any open source project that can help me build &
manage, preferably through a GUI, a multi WAN firewall gateway to the
internet, with DMZ, load-sharing, traffic bifurcation on priority/port
and auto-ISP failover on any WAN link with IDS/IPS, NAT & VPN features.

I am not necessarily looking for a firewall distro...but various
components that come together (on a minimal OS install) to build a GUI
based firewall & internet gateway appliance, having the multiple WAN
capability.

I basically want a minimalist design, which is open source, free and
offers the above features.

Some examples are the IPcop, m0n0wall (plus multiple WAN links)
Sonicwall, Watchguard, Fortigate etc., minus their additional
applications like mail anti-virus, mail servers, web-servers (except for
whatever is minimal need for GUI) etc.

Hope someone can suggest a good solution.

With regards.
Sanjay.