Anyone seen one of these?

[rickshaw]

A hand operated "airbrush":

http://cgi.ebay.com.au/3D-Hand-Airbrush-modelers-/370287927165?pt=LH_DefaultDomain_0&hash=item5636e15f7d

Can't see it producing very good results, myself.

[Weaver]

Not seen one like that, but I've got a gizmo with a squeezy bulb and a holder that blows ink off the tips of felt tip pens. Works okay within it's limits, i.e. it's good for single puffs for "splatter" backgrounds and the like, but it's no good for continuous coverage and of course, it doesn't work with model paint.

I'd imagine the one in the auction is okay for weathering effects and the like, and it probably beats setting up a conventional airbrush when you only want a tiny patch of exhaust stain. No use for painting the whole model though.