Has anyone ever tried to re-root a Drosera? This D. madagascariensis is growing really long and the stems seem very frail. I thought about rerooting the 'heads' but don't want to kill it.

I would take some leaf cuttings and plop them into distilled water to start new plants. Not sure about re-rooting, I suppose you could try one.

I did start a second pot of plants. But if I break one of these long stems, I was wondering what my options were.

I did accidently break the long stem of a D. capensis. I stuck it back in the pot and so far, it looks pretty awful.

My quick-and-dirty method is to throw things into a baggie with lots of live sphagnum and seal it; and into a very bright place where the sun will never touch the bag. Works on almost every CP.
Dried long-fiber sphagnum is a distant second-best medium.
I've never cut back madagascariensis, so I can't tell you for sure if it will break from the base, but most Drosera do.
Keep us posted on how it goes.