We removed the old open page checkout and created a much faster an TRUE One Page Checkout. This one is actaully One instead of Two pages and we have used UIkit 100% here and made the whole code base much more effective and easy to work with.
Its now bundled in the latest version 2.0.12 so just donwload this and you find it there now.
We have already a few feature requests for it and will create new version next wekk for it. Upgrades will be easy so dont worry!