I love what those guys are doing. There are lots good steels that can be found from recycled materials. Springs, saw blades, files, chainsaw bars, etc. It's most important to learn how to heat treat the steel than what the steel is. I recommend that if you use recycled materials that you find a consistent source for it.
One of the things that we've done over the years is to take materials that have a connection with the customer and forge it into the Damascus, making it personal for them. Lots of fun.
As for handles, the weirder the better.
Love and respect
Hoss