Nope. That looks like a 10-speed rear hub converted to single speeder by moving spacers and gears on the cassette. A pretty smart idea, but I would have gotten spacers so I don't need to use any gears. ... So cleaning is easy.

You might want to google for a suicide hub. Should turn up a lot. (You see most of these are just single-speed hubs fitted with track-cogs without "proper" lock-rings) But it doesn't do you no favors. Your backpedaling experience is gonna become extremely risky, so inevitably less fun.

As for welding cassettes, you find an article here.

http://www.63xc.com/mathieson/cheaphub.htm

But I read some place that cassettes aren't tough enough for "fixed" riding. ...

Yeah, for Maximum Fixed Pleasure, you ought go get a track wheel set. No hustle. While you wait for the wheel set, you can settle with the tweeker. But it might be waste of your time.