Merge difference MySQL DBs into a single new server
This consider all database names are different on all server. 

As you said all servers are mysql 5.1, You can take mysqldump on each server and restore it on new server

Step 1 :  Take dump from all old server like below

Everything written in one file: table structures, indexes, triggers, stored procedures, users, encrypted passwords.

mysqldump -u... -p... --routines --triggers --all-databases | gzip &gt; MySQLDataServer1.sql.gz

mysqldump -u... -p... --routines --triggers --all-databases | gzip &gt; MySQLDataServer2.sql.gz

mysqldump -u... -p... --routines --triggers --all-databases | gzip &gt; MySQLDataServer3.sql.gz

mysqldump -u... -p... --routines --triggers --all-databases | gzip &gt; MySQLDataServer4.sql.gz


Step 2 : Copy dump from all old servers to new server

Step 3 : Extract all zips on new server

Step 4 : Import extracted dump files on new server like below

mysql -u... -p... &lt; MySQLDataServer1.sql
mysql -u... -p... &lt; MySQLDataServer2.sql
mysql -u... -p... &lt; MySQLDataServer3.sql
mysql -u... -p... &lt; MySQLDataServer4.sql