Just a tidbit of info... The path to the registry entry mentioned above is for "default" instances. For named instances use:
[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Microsoft SQL Server\\MSSQLServer\Parameters]
Stop SQL Server,
Move master(mdf+ldf),
Change the above path,
Start sqlserver with switches,
detach other dbs,
move other dbs,
attach other dbs.