FitzTheRuke
Legend
Me neither. Maddox, the guy who tried to vivisect Data, being the person who eventually realizes Data's dream of creating a daughter (or two) is poetic. Making him a deliberate villain would be an awful, nonsensical choice.
It's more likely that Maddox and Data became allies over time and Maddox assisted in the creation of Data's daughters, or at least observed. Now, why Data never mentioned working on them to Picard is another question... I mean. the only time he could have done it would have been in his spare time while still under Picard's command, right?