Suggestions: wifi networking in Toronto city core

I'm in talks with some people to set-up public wifi internet access in
downtown Toronto. I see a bunch of ways it could work but I'd like to hear
suggestions of anyone with experience doing something similar. I want the
public to sign up (i.e. see a registration page when they try to go to a
website) before using the network so I need to use something like nocatAuth
which is easy if I use Pentium-class machines and harder with commercial
routers. The cheaper the solution, the more APs (access points) we can
have. Here's a few ways I see it can be done:

1) Pentium class (Linux) machines with wifi cards ($50 for computer, $50 for
wifi card)
1a) Have a few APs with internet connections and use a repeater network
to share the connection between many more APs.
1b) All APs in the network run in ad-hoc mode with a few sharing
internet connections and the public must connect to the network in ad-hoc
mode themselves. If the public laptop users wouldn't mind being repeaters
too, this would extend the network as more and more people use it.
1c) Have an internet connection for each AP meaning fewer APs but higher
speeds.
2) Commercial routers ($100)
2a) Use a commercial router to share internet access. Redirect all port
80 traffic to a web portal where they can browse the web, check email, etc.
2b) Flash the commercial router using OpenAP
(http://opensource.instant802.com/what_is_openap.php) so it will function as
"Simultaneous Bridge + Access Point + Repeater". This is basically the same
as 1a. A few APs with internet access will share their connection with a
series of repeater APs.
3) Commercial APs ($185)
3a) Something like Sputnik (http://www.sputnik.com/products/ap120.html)
you just connect to the net and it works.

What do you think about these options? Obviously, the Pentium machine
option would let me have the most configuration options but would probably
go down more than a commercial router. Would it be less trouble to go with
a commercial AP like Sputnik?

The advantage of the Pentium machine option is that people could donate
equipment to the network. A wifi card here, a 233MHz machine there. It
would definately be the cheapest.

Will DSL connections at several APs be enough to run this type of network or
do I need to go ISDN or T1?

Anyhow, I'd love to hear any suggestions. Best regards,
Mitchua