Cool idea. I would also modify my knife, if necessary, to be able to strike the firesteel on the knife spine. The Kershaw Roughneck has a sawtooth blade on the spine to throw huge sparks. I use that example because I have that knife and know what it can do. Any personal preferences/whining against a blade on the spine are outweighed by the obvious emergency utility.

Yikes, the price of that knife has gone up to $50 on Amazon! It was only $35 a year ago. I wrote a review a long time ago saying the knife is underpriced. I hope that didn't cause the price hike.