Yes Tellnet do offer contention ratio's on 802.11b links.

We do things differently to 1stBroadband, we have full control over the entire wireless connection from our Access Point right upto the Customer Premmis Equipment - which we provide :)
It's not the Wireless link that is contended as such, it's the connection out to the internet - the same way that ADSL contention works :)
I can offer you the following contention ratio's 20:1, 5:1, and 1:1 - obviously increasing in price :)- and at various synchronous speeds.

I believe I'm correct in saying that our wireless network is considerably different to 1stbroadband's. We have our own backhaul network to our own core POP in Penzance. Some of the backhaul is fiber based and some wireless point to point. Once back at the core POP, we have some nice large pipe's to the internet :). The actual contending is done on our main cisco routers prior to sending the information to the internet.
As we use real public IP addresses to the CPE boxes, contending a connection is actually very simple - I simply add the IP address to the correct contention vlan and it's done.

1stbroadband may also do things like this - I don't know exactly how their network is setup, but I do know how ours is.

HTH
Jon Lawrence
Network Manager
Tellnet Internet