I would like to see a JavaHelp onechunk variant.
For me it worked to copy over the content except of the import of onechunk.xsl to a customization layer over javahelp.xsl.
The only thing I had to change was to replace
otherwise the jhelpmap.jhm contains only the anchors as URL and JavaHelp doesn't cope well with that. At least the shipped demo help viewer only shows the content of jhelpmap.jhm in that case.
Maybe there is a better way to dynamically get the onechunk filename.