I did a quick multi- camera edit of HM100 and EX1 footage of a dance performance. One can see the rolling shutter of the EX1 during camera flashes. Overall, I think the HM100 and EX1 combo is a good combination.

Follow link to watch video.
Hamlik.com Fresh Attitude Dance Studio 2009 (http://hamlik.com/wp/?p=381)

Judging from the flashes, it appears that the EX1 is the wide-shot camera and the HM100 is the floor-level camera?

Correct, 2 difference performances, EX1 is the wide shots both days with the HM100 on the floor.