Place i found here in Australia selling the following:
MAGLITE MOUNTING BRACKETS C or D CELL - MODELS ASXCAT6U - ASXD026U
They look like standard maglite accessories, perhaps 2 clips on a short flat piece of aluminium would keep it steady, that also gives you a platform for handlebar mounting, not an exact quick bolt-on but might be a start for a DIY ! :thinking: I can post the link but a google with those models should give you a look at them.. btw I'd velcro it on as well whilst riding, nothing worse than seeing things bounce off the bike when you hit a bump !!
Steve.