I don't think that the porteur bars are particularly similar to moustache bars - the bends are very different. The long-ish forward curve on the moustache bar where the levers are mounted just is not there on the porteur. I've been thinking about the porteur too - but the best I've come up with are the conventional "city" levers (http://www.velo-orange.com/cibibrle.html) from V-O. These are available in the right size to mount to road diameter handlebars and cost only $11. Good luck, let us know how your solution works out.