Network Configuring through ..... Interesting ways ...

While looking into a old router sittin around I began wondering if it would work within a Cable Modem Box.
The model of the Actiontec is #GT704-WG. Basically a ADsl Router...
configuration files if anyone has worked with such hardware shows in its http administration a WAN Config that consists of
Transparent Bridging RFC1483 Bridged.
Obtain a IP through DHCP. w/ option RFC1483 Bridged / Routed
Specify a Static Ip. w/ option RFC1483 Bridged / Routed
NAT On - Off ?

I have used the Obtain and made a passive connection through the router by not using a dhcp through the router... Wont query Modem dhcp or gateways if enabled dhcp through the router.

What im wondering is if theres a way to work around this... Basically in some way of turning this type of Router into a type of Hub or switch?
Or if anyone has done anything with this before.
Just a clever thought i had and wondered if it would work..

If this cant be done with this type of hardware... Would i be able to use this type of passiveness to Setup a Bridge on Lan to Wireless (Ad-Hoc) to alternatively get past that issue to atleast get another system on the net.