I bought a fantasea housing for my coolpix P4 about a year and a half ago from JackConnick here on SB. The housing has worked out great and Jack has been very helpful in post sale support. I'm not completely happy with the controls on it (I can live with it though), but I saw that they redid the design on the newer housings (the housing for the L18 is one of the newer ones) and they are the way I'd like mine to have been. If I had to do it over again, I'd still chose it over the Ikelite housing because it is much smaller, a bit cheaper, and the 1 year flood insurance is a nice bonus (fortunately, I never needed to use it). I have a P5000 now and am still deciding wether to house it or not (it's winter now here & most of my surplus funds are going towards skiing). If I do eventually house it, I'll very likely go with the Fantasea housing (the new design) and get it through Jack again.
I can't comment on the nano strobes since I bought a more powerful Sea&Sea strobe.