Inon have recently released an M67 adaptor for the TZ30 as well as a wide angle wet lens.
I had the opportunity to test this out recently.
The wet lens also works with the TZ10 housing if you have the M67 adaptor for it.
Not quite wide enough to get a full Snell's window, as you can see on the third picture, but enough to get a reasonable effect. The dome port is being released this month, which will make it much wider.
In combination with the close-up lenses and a couple of lens holders, I can now swap between macro, wide, CFWA, HD video and stills underwater. This gives a measure of versatility if you have diverse subject matter.
If anyone is thinking of getting this, it is worth noting that the basic TZ30 with a strobe can do well in about 70% of most situations. These wet options add a little 'wow' factor to the pictures and allows more options for artistry in the pictures.
I added a float arm, following the example on the Inon website, which I think is helpful.