singlespeed hub gear conversion

[galaxy1]

Hi,
I was wondering what sort of singlespeed mountain bikes are available that are light and not silly money. I'm toying with the idea of fitting hub gears to one and taking it touring.How are hub gears for off road riding?Will they handle it or is there a point where they'll just explode?
Anyway,just an idea at the mo'

 

[RedBike]

Riding off-road puts huge stresses on the gears. (Straining in low ratios to power up that rocky incline) so I wouldn't worry too much about the gears being low/strong enough for loaded touring.

No idea which frame/bike to go for though.

I'm looking at a planet-x inbred for off-road touring. They come with horizontal / sliding dropouts so you could always use a geared hub with one of these?