If you want to have a proper HTML5 browser on Amiga, the only realistic way is to use WebKit.
It would be quite easy to port using Odyssey sources, even, but obviously, it would only make sense on UAE setups, considering memory and cpu requirements.
@magnetic
There is so many hoops to jump through, compiler probs, IDE probs, tricky gui stuff to integrate, etc
If by IDE you think about GUI editor, there's zero need for that in that kind of application development. In any serious development, you always leave this GUI editor sh*t behind, it's always a loss of time in the end (i have enough experience with XCode and Visual Studio to know how horrible they are).
As for compiler, GCC4 toolchain is enough, and editors like Golded or Scribble are good enough. Only issue might be libnix too outdated, but it can easily be completed.
And there's no tricky GUI stuff to integrate. Coding with MUI is really easy compared to similar stuff you have to do in other toolkits, actually.