Hi derpuma,
A few weeks ago I was the one hoping someone would make an arch-image with working xbmc pre-installed!
If I were to make an image of my working install I would have to put lots of effort deleting my personal stuff and passwords etc for other software I installed, so I would prefer to just help you out getting xbmc to work on your current Arch image.
I know this thread is long, but basically all the information is in here to get it to work. All the packages needed are in the official repos except the kernel, which needs to be custom made with support for the Vivante graphic chip.
1. Get Ralix utilite kernel from earlier in the thread. (I can perhaps host it for you if you give me some time)
2. Create the boot.scr in /boot as described by me in post from yesterday
3. Install xbmc-imx-git from official repo. This should pull in some other packages like imx-vpu, firmware-imx, gpu-viv-bin-mx6q-fb etc. Xbmc should work out of the box, but the file permissions are still set up wrong for the HDMI-CEC so If you use that you need to run xbmc as root.
And I think this is it actually, or did I forget something?