Video Mem too much and not changeable trivially

[turbooster]

In linux-ac100 3.0.27-1.1 (Precise) the kernel command-line could be changed be editing /boot/bootimg.cfg for example changing `cmdline= 448M ...` to `cmdline=496M...` (see http://www.altechnative.net/?p=370). This helped a lot in this very memory-constrained environment.
This is not possible anymore except for (maybe) compiling a kernel oneself.
I consider this a bug because a) OOM situations are way more frequent like it is now - and - b) the video-memory isn't even needed if the proprietary driver is disabled.