The Varavon Sliders come in a few variations from Slim, Mini, EX, and ENG models. The 'Slim' is the smallest and narrowest version of their slider weighing in at around 5lbs total. It's the common roller bearing carrier design, so it's very smooth, and friction can be adjusted with the bearings.
Old video above of NAB 2011 where we first saw the Varavon Slim video camera slider. Normally even the smallest and cheapest Varavon slider will still run you about $600 dollars retail (seen here), but yesterday there's been a few listings of the Slim Camera Slider on sale for just under $330.
Right now, that's a bit cheaper than even Konova's 31.5" (first gen) slider. The Varavon ultralight Slim version is the narrowest slider on the market at 42mm wide, coming in at 39.4" long, and says it can carry a max payload of 19kg (42lbs?). You'll find those Varavon Slim Camera Sliders on sale following the link (click here)
Varavon Slim Camera Slider 39" Roller Bearing