If you want to take your chances with eBay China, searches I ran got a result there. We're not supposed to post links, so I won't.

However, I found about 7 different vendors, all from Beijing, China offering one from a company called Mukouc, product number MA-70055. They come as a package of 6. Somewhat surprisingly, all 7 vendors listed it for the same price...$17.50 plus $1.50 postage. All only show just the packaging, not the actual product. All list it as "Sea Demon" even though the package is plainly printed Sea Sprite. Most all claim only one in stock, and claim "last one."

If you run a generic Google search with any combo of the above terms (1/700, Mukouc, SH-2, Sea Sprite, Sea Demon, MA-70055, etc.) you are bound to get at least one vendor of these in your search results. If you go to the eBay site, and run this search there, you should get all 7-or-so vendors selling it.

FWIW. I have never bought these...never even seen these before until just now. This is apparently a new maker on the market.