A wasp, bee and butterfly.
I use a DIY system with beamsplitter and 2 x D300 nikon, 2 x AF105/2.8D macro and 2 x SB-80-DX flashes. Detection in-flight via 2 x IR laser signals and optical detector via AF50/1.8 lens. Stero-base adjustable between 0 and 15 mm or more if needed.
The full description stay on my flickr site:
Inclusief mechanical details, electronics and PCB design.