As they had a total of five offices and they wanted a separate connection for each of those links (for, again, no good reason), we needed seven total NICs...

Ouch! I think back in the early 90s a lot of companies built frame networks that looked *just* like their existing point-to-point networks -- some combination of being unclear on the concept and maybe lack of trust in new-fangled frame. 'Course, all those interfaces were probably going through the same carrier frame switch, but everybody felt better!

On the clueful side of the equation, having all those interfaces could possibly make sense if you had multiple carriers/networks and multi-homed local loop/s, but somehow that doesn't sound like it was the case.

Y'know, back to the original query...I suggested another NIC without knowing that server already had 2 and was serving Internet sharing. I'd say the additional (3rd) NIC is still a decent idea, but admit that it could be marginally more complex if that server already has masq/ipchains-type services configured that would need to be tweaked.