Modprobe blacklisting using kernel command line

I have two boot configurations which more or less look like this:

1. modprobe.blacklist=nouveau
2. modprobe.blacklist=nvidia,<and other nvidia modules>

Which serve to dynamically use the open source or proprietary driver when booting. Now I want to add another boot entry which disables both nouveau and nvidia in effect disabling the NVIDIA GPU.

3. modprobe.blacklist=nouveau,nvidia,...

lsmod | grep -iE '(nouveau|nvidia)' still shows nvidia so my guess is that another module pulls that in.

Normally I could create a file /etc/modprobe.d/blacklist:

install nvidia /bin/trueinstall nouveau /bin/true

But this would mean that I loose the lexibility of just choosing another boot entry.

Is there any way this behavior could be achieved? My only idea was to have two small filesystems which contain different modprobe.d configurations and mount them dynamically as early as possible during the boot process after changing to the real root partition.