Thanks for all the suggestions! I'm not stripping heavy gauge wire daily, but it seems to come in waves. Sometimes it might be once a month, other times it seems like I do a few in a week. It's been one of those weeks and once again I'm wishing I had gotten around to buying the right tool before. Blades and knives are alright, but it takes more time to get a nice square cut and not nick any copper strands. Plus like cosmik said, any excuse to buy a new tool!
The Greenlee and Knipex models look nice, and I wouldn't question the quality of either sight unseen, but they're a little more spendy than what I was hoping for. And the 2x4 with a wood screw (actually I'd probably use multiple holes sized for different gauges) ought to work nicely, but space is at a premium in my 26" stacker, even after I just added an intermediate chest.
I think I'll try a Jokari or the rebranded Anchor. Amazon suggested a similar model from Ideal too that is made in the USA. Anyone have any experience with the Ideal model?