After some more coding today, the results are promising. It works with SVGs, not raster images, so you can have perfect scalability and do the fractal-y stuff down to whatever level you want. There's still one big problem; I have to find out what's causing it.
As to platforms...well, the code is in C++ and very portable. I'm developing this on a Mac (which I know you have). The main problem, however, is that I am not at all familiar with how to put a graphical user interface on it...either I have to learn how to use those or you would have to run it from the terminal. This is a one-guy operation, so I can't build it for Windows, Linux, or any other version of OS X. If you actually KNOW how to compile/build C++ code, that's a different matter.

Anyway. Didn't mean to hijack the thread there.

So your world is...conical? That's awesome! It does raise a lot of questions about days/seasons/tectonics/what happens to the ocean at the edge of the world. But I'm sure you will provide us with these answers in due time.
And just because your continent has the general shape of an island doesn't mean that continents can't look like that. It is completely plausible for a teardrop-shaped continent to form without any sort of (significant) eroding forces at work.