I like the alloy bottom loop on the Swenco's. Probably doesn't weigh any less than the ChroMo set up but it looks more rigid. I wonder if there is more flex in the Swenco's compared to other leading links because of the conventional type clamps used?
I suspect they aren't as stiff as the tubular steel links on the Thorks. Aluminum is 1/3 as stiff as steel, and the metal in the middle of a solid section doesn't do much work. Also, a closed box is stiffer than an open "U" channel is and resists torsional loads much better. Aluminum has 1/3 the weight, but that solid aluminum bar will weigh about 4.75X the steel tube. Aluminum needs to have larger sections to have an advantage over steel. An aluminum tube of about 1.1" OD x .187" wall will have similar stiffness to the 1x.062" steel tube and about the same weight.
A 1.05" OD solid round of aluminum has about equal stiffness as a 1" x .062" steel tube
The Swencos have a small stanchion, designed to slip into the stock clamps, and those small forks are often not very well clamped, as anyone who has fallen down and had to straddle the front wheel to twist the handlebars back perpendicular to the wheel can attest. If they are welded up there's no slippage. On John Cronshaw's very fast and successful Goldstar VRR bike he's gone to fabricated steel clamps welded directly to the telefork stanchions for less weight and greater stiffness.
http://www.eurospares.com/graphics/chassis/CronshawBSAweldedfork.jpgDeCoster/Honda used the Ribi forks, which are much more complicated (and expensive) than the normal LLFs like the Thorks. You can find some Ribi patent documents in that folder on my website.
cheers,
Michael