Compiling the linux daemon from the current Github master (v10.14 beta) and using sendmany throws an error: "Unable to locate enough Darksend denominated funds for this transaction" due to src/rpcwallet.cpp line 722: AvailableCoinsType act = ONLY_DENOMINATED;
Modifying line 722 to AvailableCoinsType act = ALL_COINS; fixes the issue but may not be the desired solution for darkcoin development. (At a minimum, I would expect sendmany to respect setting disabledarksend=1 in the .conf file at least though, which it currently does not.)
I would suggest treating this as a fairly urgent issue, as sendmany is commonly used by pools and exchanges.