?
I have many on one windows machine, each wallet has its own copy of the blockchain though
Folder structure is like this:
C:\Users\Stonehedge\AppData\Roaming\DarkCoin\MN1\
C:\Users\Stonehedge\AppData\Roaming\DarkCoin\MN2\
C:\Users\Stonehedge\AppData\Roaming\DarkCoin\MN3\
C:\Users\Stonehedge\AppData\Roaming\DarkCoin\MN4\
C:\Users\Stonehedge\AppData\Roaming\DarkCoin\MN5\
C:\Users\Stonehedge\AppData\Roaming\DarkCoin\MN6\
...
Command line switch for MN10 would be as follows. When you first execute the command a new wallet is created in the subfolder and blockchain downloaded.
darkcoin-qt.exe -datadir=C:\Users\Stonehedge\AppData\Roaming\DarkCoin\MN10\