Here's another thought: I might get a pair of these

http://www.niagaracycle.com/product_...ducts_id=33118

and use them instead of the axle nuts, i.e., put them through the dropouts with the heads on the outside, so that they extend inward over the ends of the axle. (The ends of the axle currently reach out as far as the dropouts; they just don't extend out far enough to get the egular axle nuts on them very well.)

I don't have enough experience with this kind of thing to predict whether it will work or not.