Surly Long Haul Trucker set up for commuting and loaded touring, old Sekine road frame converted to fixed-gear, various beaters and weird bikes, waiting on the frame for my Surly Big Dummy build
I'm not so sure a hacksaw will cut it (pun intended, I guess), since the axle is probably hardened steel. If a hacksaw can't hack it, a dremel with a cutoff wheel will make fairly quick work of it and will leave the threads in pretty good shape. Just threading the nut back off over the cut will fix the threads up just fine, but I always neaten them up by tapering off the last 1/2 turn of thread with a file or dremel to avoid having a sharp finger slicer. I've cut a lot of bolts for various things, but never had the need to cut an axle, or I could speculate further on how hard the steel is. I've got a wheelset with a long axle just like yours and it doesn't really bother me enough to do anything to it.