That is beyond way cool that is extremely useful. Just think you can hand hold the flash without a cord just hold the thing up.
yep - plus, you can assign different groups (meaning, different levels of flash power) to various SB-800/600 from your D300, and there you go - main, fill, hair, whatever you need, right there; the only thing is, flahses must be in the line of sight of the D300's pop-up flash
One example here with the D2x: 1 SB-800 on-cam, not contributing to the exposure, and 2 SB-600 around...
(1 SB-600 is actually BELOW the machine, something near-impossible to do with a regular-sized flash head...)