Donald Paul was asking: "I am looking for plans on how to build a 
Harmonipan.  Is this a subject you have any knowledge of?"

Well, for a Hofbauer no plans are available, I think.

Maybe this helps: http://web.telia.com/~u43000075/Orgelb.html

Another one, however in German (or Dutch):
    http://www.hobbydraaiorgel.nl/subdir/hoeffle.htm

Complete kits, unassembled:
    http://www.alanpell.com/Organ_Parts/Organ_Parts.htm

Last but not least:
    http://www.johansorgels.nl/draaiorgels/englishbook/index.htm

And there are more! 

Jan Kijlstra