River cane is a type of bamboo, so it's not really wood it's actually a type of grass. They are tougher than wood arrows except maybe for good shoot arrows(though cane/boo arrows are technically shoot arrows too). I have(in the past) shown people how tough cane/boo arrows are by whacking a raw(no point or fletching, but cut to length) shaft really hard sideways against a tree or telephone pole. Cane/boo or carbon are the only ones that I have tried that will survive this.Now, I'm not saying they wont break from doing this, but it takes a surprising amount of effort and hurts my hand. I shoot bamboo (tomato stake) shafts a lot and have yet to break one while shooting.
I don't usually spine them per se. I just make some up and use the ones that fly well or tune them by adding weight to the tip. Ferret had a good idea about spining them by placing two nails 26" apart on a wall, laying an arrow that you know shoots well from your bow on the nails, hanging a weight(usually around two pounds)from the middle ,marking on the wall how far it bends, and then do your cane shafts the same way to get a good estimate of spine.
As far as availability; if you're into harvesting it yourself then river cane should be easy to come by in OK. Other wise bamboo sold for tomato stakes can be found at wally world, k mart, or just about any garden store. If you wait till the late gardening season you can often get them for $1 a bag. On average I only get about 4-8 usable shafts from a bag of tomato stakes but that works out to...extremely cheap. lol
BTW I used to cut river cane on the Red river and the Pease river in north Tx. As well as, just about any creek bottom in the area. I even found some around culverts on the side of the road. But, it must have been switch cane, because it was almost always thin walled and a lot weaker than the mater stakes I ended up using.
At any rate, like Jason mentioned above, they are a lot of work but are well worth the effort. imo
And, the sky's the limit on how (or if) you dress them up. Judging by the leather work I saw on your site though, I bet yours will look awesome. Please post some pics if decide to go ahead and make some up.
Hope all my rambling helps you out in some way.
James