Can I downgrade X in 12.04?

view full story

http://askubuntu.com – Is it possible to successfully downgrade X to 1.10.99.* or earlier in 12.04? I have tried with Synaptic->Package->Force Version, but it only shows me two versions of 1.11.4. Downgrading would restore some broken accessibility functionality that I rely on to use Ubuntu effectively. (HowTos)