I believe Laurence Dickie designed both the Giya and the Nautilus.
If you watch this video...
...you'll see that the principles in play are rather similar, except the Giya's tapered tubes for the three drivers above the woofers are internal (as opposed to the Nautilus, which makes show of them), and the woofers' tapered tube goes up to the top, including that visible curl.
So you're absolutely right that there's some stuff in common here between the Nautilus and the Giya.
I included the PHA-1 as one of the products in the Head-Fi Holiday Gift Guide. You can see its entry by clicking here. (We haven't posted links to the guide or promoted it yet, as we're still working on finishing it over the next day or so.)
As with most of the other products in the guide, it's not a comprehensive review, as space was limited. That said, I love the thing. It's not a drive-everything portable amp, but it is a drive-most-of-what-I-want-to-use-portably amp. In terms of background noise, it's dead quiet. And its band-and-rail system (that lashes one's iPod/iPhone to it) is simple, brilliant.
Nice to see ya here Jude. I like the new web app for the forum but its still quite difficult to select and delete large sections of text, hence the large quote.
But wait, looking at the gift guide - there is a professional version of the z1000 with a tweaked signature?!?!?