and my empeg is unable to lease an IP from them, despite every additional machine having a nice 24.65.*.* address.

Interesting, I thought !@Home was a 1-lease-per-customer proposition (I wouldn't know, as I'm with a local DSL outfit...)

...putting a second NIC in my machine for my internal subnet, but thats ridiculous.

Like the man said, not ridiculous at all, but I'd say that a more comforting, more durable, and more trouble-free option (albeit more expensive - say $75 for a 1-port model) would be a cheap hardware router/NAT like a Linksys.