I wonder if the more modern varieties would fair any better than the older one's you have had. Unfortunately most arachnoideums (and velvets for that matter) seem to be less sturdy in our climate.
Sounds like there may not be any white bloomers left in the US. I'd love to use some to see a wider variety of colors in the blooms of my velvet/cobweb seedlings (which are derived from nearly all pink flowering types). V. Schara did some very interesting things with bloom colors and I'd encourage anyone with the time to spare to read through some of the notes he's made on the plants I've mentioned here and their subsequent hybrids with other colored blooming types in the sempervivum-liste.de. He produced some very distinct bloom colors in his work with these plants including cream tones, multitonal mauves, center stripes and red tipped blooms. It was a fun read and some of the photos were jaw-droppingly beautiful, I was left envious.
For what it's worth, I managed to successfully integrate a number of yellow flowering hybrids into my gene pool last year, a few of these I crossed with 'Gold Nugget' (which has white blooms with pink centers), and so far I've successfully raised raised seedlings from these crosses. What a treat it'd be to have a plant which is not only vivid but also produces unique blooms.