Is there a requirement that SQL Server should be 7?
Ask your developers. You can move 7 databases to SQL Server 2000, they are upgraded automatically with you are attaching 7 databases to 2000 server, also they will be upgraded if you backup on 7 and restore on 2000.
SQL Server 7 databases tend to work fine on the 2000 server. Then they become 2000 databases, to be correct.
Yelena