Eddie, a couple of answers to that. first, we know from history that the chances of one or two hand-placed pieces blowing are very good. the chance of the rigging material in an anchor getting cut is very very low. I've only heard of one case of this happening, and it was due to a disasterously constructed 2-piece anchor, which forced the sling to slice across a long arc of sharp rock when one of the two pieces blew. it's such low probability for webbing or cord in a normally built anchor to fail, that it's wasted attention to put too many resources into backing that up.
however, you can backup such an anchor easily by tying a backup knot with the rope onto your strongest piece. it takes just a few seconds.
my reservations about Alpine Equalizer-type contraptions is about versatility. i'm sure they work well, but i don't want to have to buy and carry a specialized gizmo that's really only designed to handle 3-piece anchors. I think Richard's invention that you show in that picture is a definite improvement on the original trango product, which has greater limitations.