In terms of a mobile version, this is something we've talked about, but I think that the only way this would really work is on the tablets, not the phones. Which is fine for you, but I'm an iPhone4 user and don't have an iPad.
One of the big limiting factors on the original iPad was that it only had 256MB of RAM, which was really pushing it. The iPad2 is a lot more promising in that regard, but optimizing for any mobile device is pretty different from doing the same for a full computer. To even get started, we'd need a couple of copies of Unity iPhone, which would set us back north of $3k. Then there's at least a few weeks or a month of development time, which would cost us even more in terms of lost opportunity.
What it really boils down to, at base, is that we don't already know how to develop for iOS -- all the tricks and techniques specific to any platform take time to learn even if you don't have to switch engines. These things always
take more time than expected.
So then the next question becomes "could we even make the money back that we invested in making the port?" My thought is... maybe. On our PC and Mac version combined, we've still only earned back about 35% or 40% of the cost we actually spent to make the game. I really love the game and am glad we made it, but we just never could get it to connect with a large enough audience to offset the cost of making it. I know a lot of iOS and Android developers (well, half a dozen), and their experiences are kind of a mixed bag. There's a lot
of competition in those markets, and not a lot of visibility unless you happen to get a big hit.
In a lot of respects Tidalis would be a better fit for those markets than it was for the PC, assuming we could nail the controls in a touchscreen-only environment (which I've thought about a lot and believe could be done). But there's still a lot of risk there, and given the financial beating I've already taken on Tidalis it's not something that really excites me, honestly. Actually, porting in general doesn't really excite me -- I'm an indie dev to make games, and I've seen what happens to companies like Introversion that spend too much time just porting endlessly.
All of that is to say, I think that the only ways a port of this game to another platform would happen were if: 1) we made a ton of money on other projects and could afford to dedicate a new programmer to just doing the port to see what happens; 2) or if we partnered with some other individual or developer who took the existing code, did the port and took the financial burden of that part of things, and then split the profits with us; 3) if the iPad3 or similar is so similar in specs to your average Mac that the porting trials just really go way down, and/or that we port another game to the platform and thus already have the tools and expertise to do Tidalis also.
We've actually talked to a couple of other indies about the partnering-on-a-port idea for Tidalis, but it's always fallen through for one reason or another. It's something I'd love to see happen, because I think playing this on a touchscreen tablet could actually be the definitive experience if it's done well, but at the same time I don't want to be the one to do it. I have easier and more fun ways to make a living at the moment is really what it boils down to.
Anyway, hope that answers the question at least!