dear Harlin,
i didn't see before the particular bug report you mentioned but i found many similar ones in the past. to me it looks as mpage under version 2.5.6 was never fully prepared for the UTF family of character encoding schemes. or it may simply miss the proper font for the UTF range of characters. that's all very sad as mpage is such a neat elegant little tool.
then, another helpful feature could be a flag for PDF output (although i am happy with ps2pdf but it's one more step to do).
in any case, it looks as if development of new mpage versions is somewhat on hold :
http://www.mesa.nl/pub/mpage/
http://www.sfr-fresh.com/linux/misc/mpage-2.5.6.tgz/
bye, pisti