The first site you linked to doesn’t seem to have a breadcrumb trail showing up for me, so I’m not exactly sure what you’re trying to replicate. Assuming what you want to do is have product variations represented in the breadcrumb trail, that could get messy quickly. Breadcrumb NavXT generates location breadcrumb trails, which subscribes to the idea that resources have one true location. Thus, having the variation influence anything before the current item breadcrumb in the trail isn’t going to really fit the location breadcrumb model. Additionally, I’m not exactly sure adding the variations to the end of the trail makes a ton of sense either. Technically, either are possible to achieve, but you’re going to need custom code to pick off what variation is in effect and add that breadcrumb (though I’m not sure what it’d link to exactly, maybe an archive for all products of that variation type?).
