My compact is amazigly fast (40 to 80ms)
No, it isn't. I have 4 SD1100s, and unless yours is somehow different than mine... You probably used a software tool like MD_Test2 to benchmark your MDFB. Well, it lies.
I'll build something with an Arduino...and let's see if it works:)
There are already a few triggers out there for Arduino boards. I myself love Arduinos. Check out Maurice Ribble's project,
Camera Axe for a ready-to-go solution. Works well in daytime storms too.
Another thing you could do, take an Arduino and few LEDs and make a millisecond timer, one that's accurate. And re-test that SD1100 correctly.