Just today I saw the new snoot from SEACAM for their Seaflash 150 and Seaflash 100. As expected, it is very clever and quite elegant in execution.
Wish I had some in-water shots to show you, but this one belongs to someone else and will be in Lembeh next week.
The snoot integrates a replacement ring at the front of the strobe, attached via a pressure fit just as the diffuser likewise attaches. The snoot element inverts to make for a smaller package for travel, and contains special light concentrating lenses to consolidate the light down the "pipe".
Here are some shots I grabbed today as it passed through the studio: