Yes, sharpening these saws is much easier than a handsaw. You have all the space in the world that you need to work, and all the angles are easily visible. You can do the job with an off-the-shelf flat file.
Ordawg, I've sharpened ours. I don't think I did a great job of it, but it cut, so there was some degree of success. Like everything, I'm sure I'd get better with practice.
As far as the sheath, that's a really fancy and nice one. It might almost be worth a whole cow. <img src="/ubbthreads/images/graemlins/laugh.gif" alt="" /> On ours, we took a four foot section of castoff fire hose (the fire department replaces hoses on a regular basis; ask your local station if they will give you some!), and slit it down the length. It's rubber inside with a canvas jacket permanently glued on. We hook a bungie into the hole where the front handle bolts on, wrap it around the whole affair a few times, and hook it onto the handle. Not pretty, but real cheap, and it protects us from the saw so...
I have wondered before what a sawblade made of INFI would be like. <img src="/ubbthreads/images/graemlins/crazy.gif" alt="" />