I love slidify too and I think that having similar functionnality in org could be great.
I think that you have everything to do that using the html backend, you just need to interface the right Javascript/HTML5 library.
In slidify you can use io2012, deck.js, shower and landslide and I know that you can use deck.js through ox-deck and it will not be difficult to create and interface for other library too.
For example if you need a nice non Beamer library you can also check
ox-reveal which interface reveal.js.
Here is a minimal example with R code. (Make sure to have ox-reveal.el in your path and export using C-c C-e R R)