How to emulate the Raspberry Pi 2 on QEMU?

Some time ago I emulated the Raspberry Pi following this article, but this approach has several problems:

1. It is very slow.
2. The display solution is limited to 800x600.
3. You cannot emulate more than 256mb ram.

Furthermore there is no emulation for the new Broadcom BCM2836 or any other arm7 based cpu in Qemu. However, there are several reasons, why it would be interesting to emulate the Raspberry Pi. So I am interested in any hints that push me in the right direction to get a working Raspberry Pi 2 emulation using Qemu or any other emulation software under Linux.

If you're comfortable building qemu, you can find support for pi2 system emulation here: https://github.com/0xabu/qemu. It's not particularly speedy, and the device emulations are incomplete, but you can resize the RAM and framebuffer.

There are brief instructions for booting Raspbian at the end of https://github.com/0xabu/qemu/wiki