Have the sources of MorphOS ports of various games and emulators such as ScummVM been released? There are some things that I'd like to get to compile on AROS, I'm no coder, but I thought perhaps the changers made in the MorphOS version of certain programs might increase my odds of getting them to compile.

First place to check is the place where you download the binary - often it's in the same dir with -src in the filename. Otherwise, you can ask the program author. In some cases, you don't even need to make any modifications (f.ex. Reminiscence), or sometimes people want to add features (VecxGL).

Did quite a few modifications to get xu4 work, but didn't release the sources yet, as there are some issues. If interested, see the relevant thread, I'll post a reply there.

Finished or not, people are still entitled to get sources to any GPL binary if they want, but often (when the purpose is to port to other platforms, for example), it might be a better idea to wait until it's more "finalized".

Well I wrote Fab, but he must be busy as it's been a few days and I've not heard back from him.