Novel technique, with only one drawback (minor) that I can see : the display:none; property on the .jumpto class. Neither robots nor screen readers can see this. But it's not an issue that can't be tackled with, visibility: hidden; or text-indent: -9999px; methods. (They do have 'names' but I never get them right without first searching. The methods are familiar, though.)
As to Nav? why waste a unnecessary wrapper on it. I mean, unless you don't already have a block level wrapper there is no reason to waste code on any of that extra HTML 5 bull.
But I say the exact same thing about HEADER, SECTION, ARTICLE and FOOTER... pointless wasteful unnecessary crap to stack on top of the ridiculously loose structural rules that make HTML 5 more a trip back to 1997 than improvements to coding practices compared to 4 or X1.0 STRICT!
As a matter of fact, these are free standing blocks, child elements of the content wrapper, or page wrapper, as the case may be. I admit, DIV is just as appropriate, and doesn't require restyling. But I'd like to get my feet wet, and have started with something a little less complicated, the footer and hidden navigation.
I'm finding that IE 8 with a shim is still spotty on styling HTML5 elements, but the revised styling on the anchor solves this. It's not a debate. Whether I like it or not, I would still like to be able to add HTML5 and CSS3 (and eventually the new DOM) to my repertoire just so I can have a chance to learn the in's and out's, and quirks as they may arise.
In five years I will have forgotten all the tweaks and the reasons behind them. And just like a decade ago, everything will eventually fall into place.