I have 6" DPN's in aluminum... got them on E-Bay. The only time I've seen shorter is when I break one of my wood or bamboo, then I re-point the broken part to make nifty little DPN's for doing the fingers on gloves. Hey, as long as your making DH warm with your knitting, why not ask him to do a little machining to make you some short aluminum DPN's? That is, providing he's not one of those 'Tim the Toolman'-type goof-balls, and you end up having to knit him a recovery sleeve, or, God forbid, an eye-patch.
Or maybe just forget I said anything.