The problem is that darkcoind won't save more than a few hundreds of keys into the wallet.dat, no matter how big keypool I ask for (it does generate all the 10000 or more keys into the thin air but saves only ~500 initially and only ~200 new after it flushes those original 500 unencrypted keys when you later encrypt the file) and I figure DarkSend will eat the keys from the keypool like a crazy addict, and thus you will either need to periodically input your password on the online server (risking your coins if somebody hacked it, even more if you do it automatically and thus you keep the password on the online machine) or copy the wallet.dat to a flash drive, refill it's keypool on an offline computer and copy it back (while your masternode is offline).