Dave, I think that Calibre would be 'nice' to have ported it is not really an epub editor, its main strength is in e-book file type conversion. Sigil, on the other hand is a true epub editor and does that job exceedingly well, even the very old version that Paul ported - a newer version which has extra features would be the thing although I can't remember which version it was when it changed to using the next version of Qt4 above the one we have.