These things are certainly possible with only small modifications to the code.
I have some, as yet unpublished (because adding even more changes into rewrite will delay release even further), code that does similar things, e.g. loading renderthemes from apk assets. The following code snippets just might give you an idea what to do:
Loading a render theme file from assets by deriving an AssetsRenderTheme from XmlRenderTheme:
public AssetsRenderTheme(Context context, String relativePathPrefix, String fileName) throws IOException {
this.assetName = fileName;
this.relativePathPrefix = relativePathPrefix;
this.inputStream = context.getAssets().open(this.assetName);
}
It is equally possible to add your own icon bitmaps from apk assets.
Once 0.4 is out I would like to merge it into the trunk, but I do not want to delay things further at the moment.
Ludwig