I used to be a drag & draw drummer, then I got something (the SPD-20 below) that I could hit that would create the MIDI notes for fills that were impossible to figure out mathematically. Eventually, that grew into the below (which my friend now owns). So much fun! I still stink at drums, someone told me they require good timing (any idea where I can buy some of that?).
Ok, now on to the option I probably SHOULD have taken! Find someone who's an actual drummer and work out something where they'll create some real fills (or maybe even play the drums for the entire song) based on a basic MIDI track.
"Great! Now can you do the trick that makes a sound like 'pea soup' 'pea soup?'" - I've actually heard this one. They wanted the sound you get when you use the high-hat pedal just right. LOL! ?