Hardware

Hi, I'm developing a Wireless ISP proyect, and I wanted to know if you could help me in some choices to make,

I'll setup a fiber optic E1 wich is a Full-Duplex 2048Mbps connection, and we're expecting 1000 users, and having in consideration that we'll need a Captive portal, and per user limit bandwidth I wanted to know some of the options that I have.

I've an Alix 2c2 running m0n0wall 1.3b and I have finally set it up to limit users bandwith by IP address, and the Captive Portal working, the thing is I don't think the Alix can handle 1000 users, with the basic firewall configurations, NAT, with different bandwidth (As an ISP I'll be assigning different speeds acording to the speed the client pays for), so would you recommend me a server or a simple PC with enough processor will do it?,

Also, this may be out of line but, I've been checking the Nomadix AG5500, and it does everything I need (user Authentication and per user bandwith limit) and I don't know wich solution would be better, a device wich is specifically designed to do this for 2000 users or a server with m0n0wall or any other linux distribution.

Thanks in advance.