Hi Andy,
Becuse E-smith does not , by default, support any DSL connection, except through ethernet you are limited.
I have now got the Vigor USB router, 'it does exactly what its says on the tin' but I cannot get the server to use it as its internet connection and work as a proxy as well. At present the Server and the 'clients' are all directly connected to the Router. I find this very annoying for security reasons but other than that it works brilliantly, even seems to increase the speed of the connection.
In your case, I know for certain that the Alcatel modem will work correctly with smoothwall. You could have 2 servers, Smoothwall for the firewall and E-smith behind it, doing everything else. It probably works out about the same as buying the Vigor Router (cost wise) but Smoothwalls Firewall capabilities will greatly exceed the Vigor's system.
If you do go for both, please let me know how you get on and how you get e-smith to correctly recognise Smoothwall as the Internet Gateway. It may help me to get my Vigor and E-smith server working the way I want them to.
Good luck