I'm not a big fan of either design. They both look unnecessarily heavy and complex.
The eBay pot stand is heavy (2.5oz) and all it does is support your pot. There are much lighter and simpler ways to do this, like buying alcohol stove with an integrated pot stand.
The Trangia pot stand/windscreen thing is way too heavy (4oz) and it looks like it does a poor job as windscreen since it doesn't even come up as high as the bottom of the pot. I imagine you'd get poor real world performance and fuel economy with one of these unless you used a proper windscreen as well.
Simplicity, support, stability and weight of my cook system is an area I've been thinking about a lot lately. I really like the stability of the Caldera Cone, but I don't like how it doesn't store in my pot. I have one of the shorter Caldera Cones (ie. ULC or Sidewinder) so it fits into my pot, but then I need to carry two stakes (8g ea) which adds a significant amount of weight and complexity. For me, these two stakes aren't multi-purpose because I want to be able to cook and have my shelter set up at the same time. Also, stakes usually don't fit into the pot, so you have to go digging around for your stake bag which is unnecessary hassle.
My conclusion is that the best setup is one where the stove functions as the primary pot weight support, but the windscreen hugs the pot to add much needed stability. So essentially you'd use a short Caldera Cone (ie. ULC) but without the stakes and instead the pot would rest it's weight on the stove. A nice low stove (ie. Zelph Starlyte) is ideal.
IMO, Trail Designs should consider doing something like this. All they would have to do is add a few grams worth of a pot support onto their 12-10 stove and then users of the Sidewinder and ULC systems could ditch the stakes. It would be a lighter and simpler system, while still retaining excellent stability.