|Any ideas in making FTP go faster?|
Make what exactly go faster?
You mention the time it takes for the connection from a Windows 7 box to the ftp server (5 seconds) but nothing about data transfer rates. Are you having slower than expected transfers as well, or is the delay at login the only issue?
If the login delay is the only issue, I suspect it would have to do with the difference between logging in with a Windows based client as versus another SCO client since you tried both ways and there's no delay with the SCO to SCO connection.
I don't know if this is something you can do anything about, especially if it's because of the windows based client. I would suggest try connecting with a few other Windows based clients (both XP and 7 if possible) and see if the issue is the same on all of them. If it is, then it's a Windows issue and there isn't likely much you can do about it.
It matters not how straight the gate,
How charged with punishments the scroll,
I am the master of my fate;
I am the captain of my soul.