What I've used is the SMC Perforated Snow Stake (also useful in soft earth): http://www.backcountrygear.com/catalog/accessdetail.cfm/SMC225

It's aluminum and fairly long, so the downside is that if you're not a bit cautious, you can use the leverage to bend the tip, after which it's never as strong in future. Still, I've used this as my only hole digging implement for something like 3000 miles now, and only bent it a couple of times. At $1.50 each, it's a cheap thing to try, and maybe useful for it's intended purpose too

If you want to make it a little more comfortable to hold, dip the top couple inches in plastidip.
You might also want to file the edges a bit to smooth it out (remove small metal burrs), depending on how you carry this on/in your pack (I slip it in the external mesh because ... well, when a body has to go, a body has to go!).