AN UPDATE
Okay all I am still notable to see any WLAN but id extensive testing an wanted to post so not only those who are trying to help but those in future that may see this issue have this documented.
FIRSTLY THE SETUP
SMC Wireless Router - Barricade G 2804WBR
Samsung 120HR (originally) DTIVO Modded with 4.01 SWare
Linksys WUSB11 Wireless B USB Network Adapter V2.6 (confirmed)
INITIAL TESTING
1) Okay I first had a newer WUSB11 V2.8 which I plugged in and sure enough was not recognized so I then went on the hunt and found a V2.6 which as soon as I plugged it in I got the message that it had found an Ethernet adapter. With this info in hand I plugged away setting up the WLAN on the TIVO which at the time was completely closed with WEP 128 and no broadcast SSID (BSSID) on chan 8. The TIVO responded with cannot locate this network. Also worth pointing out MAC filtering was enabled at this time but I had already added the MAC address. Wireless signal read none.
2) With the above in mind and the fact that I am using a Linksys and an SMC I decided to change my WEP key to 64 HEX and rename my SSID to something simpler (no special characters) and try again, this still did not work. Wireless signal read none
3) After this I disabled all firewall settings on the router, removed WEP security and enabled BSSID and still it could not locate the network and the wireless signal read NONE.
4) I decided to try again the same as step 3 but this time physically carted my TIVO upstairs and sat the WUSB11 on top of the router (was thinking about drawing an arrow on paper to show the data flow to the adapter  ) but still absolutely nothing.
5) I now wanted make sure the adapter was not faulty so I removed it from the TIVO and plugged it into one of my laptops and boom straight away not only did it pick up my WLAN but 4 others (as expected) in my neighborhood.
So what did this initial testing prove, well in summary it proved the adapter works and seemingly has no interoperability issues with an SMC router running or not running WEP. This also proved that BSSID was in fact enabled as the adapter could see it. It also proved that there was no other issues router side that were blocking the TIVO from successfully connecting.
After completing the initial testing and spending days scouring the web for insights I also tried changing channels to non overlapping ones like 6, 11 etc but still nothing and that is when I had a little bit of a brain wave. I thought maybe if this USB adapter was dumb and held its settings in VRAM that I could plug it into the PC and configure it that way first then transport it back. Sure enough if you use WLAN monitor to setup your default profile it writes that info back to the adapter and saves it (confirmed through advance networking setup/configure adapter). So, in the end I now had a complete config on the adapter that worked flawlessly when plugged into the laptop. I plugged this into the TIVO and
NOTHING, same problem.
That is where I am right now. Two things I noticed on the site survey completed by WLAN monitor though was that when WEP is configured on the router and even in the Linksys profile the WLAN monitor shows WEP as disabled on the router and indicates the BSSID as the WLAN mac address of the router instead of by ASCII name.
So, I dont know if this will help but at least it is documented for everyone. I am picking up a WRT54G tomorrow to test with to ensure once and for all that there are no hidden flags or interoperability issues between different manufacturers. Maybe the TIVO is that dumb it cannot be flexible in any way to the change in possible WEP configurations from device to device (even though it is a standard).
Oh well, hopefully we will get there because being an IT Infrastructure Manager by trade this thing is really bugging the crap out of me
WC