Dynasty DGRS-30-4 oven thermostat

I've got a Dynasty range, model DRGS-30-4. The oven keeps overshooting the set temperature, blowing way past it every time we use it. I want to replace the thermostat. Ordered the replacement from partstore.com but after 2 weeks they wrote me back that it's no longer being manufactured. Dvorson's, in California, seems to be the only place that has most parts for these (we've bought a couple things here and there from them over the years), but when I called them today they said that part is no longer manufactured by anyone and basically we're out of luck.

I don't want to have to scrap this entire range, because it's great in every other way. But we really can't not have an oven, so I need to do something. I'm comfortable working with electronics and electrical stuff, but I don't really know where to start when looking for a replacement thermostat. The cheap universal ones I'm seeing around, like on Amazon, don't have the right sized dials (the Dynasty has a big, chunky one) and it doesn't look like our knob would fit on the shaft they provide.

So is there any hope here?

Thanks!

via Dynasty DGRS-30-4 oven thermostat
by friolator