Here's my drum trigger patch that uses just native objects, locks out each trigger (so they don't trigger each other), does velocity, etc....
With velocity there's a tiny bit of latency (180 samples), but it's better than a hardware unit I think.
It's tuned for 'on drum' piezos, so it may not work well with drum mic input, but I've not tested that.
I used the DDrum triggers, physically on my drums, but it should work for any similar/piezo/head trigger.
The volume differential bit is based on Peter McCullough's envelope follower.