I'm in Ocean City, MD for the Maryland State Firemen's Association convention, and Mobile Fleet is repreaenting Whelen. They have a Mini Freedom with at least three of the simulated rotators, as well as a 4500 series with two of them and three 700s.
I've been looking at them long and hard, and I think it could work, but the patterns leave a lot to be desired, from what I've seen. I think that a faster oscillating pattern (sweep versus rotate) and maybe even a negative rotating (instead of having one column of LEDs on at a time, all but one would be on. The off column would appear to travel, just as the on column does now) could be useful.
I also think that these, installed in a 4500 series, could be great for off axis lighting.
I'd even sugggest a larger frame to allow for some work lights beneath.