Well I tried the .28 kernel with the package versions you suggested, and when the X server starts, it's just a black screen BUT the machine doesn't freeze and there is video output, it is just black. These lines seem relevant in the Xorg log:
(II) GLX: Initialized DRI GL provider for screen 0 (II) intel(0): Setting screen physical size to 304 x 228 [config/dbus] couldn't take over org.x.config: org.freedesktop.DBus.Error.AccessDenied (Connection ":1.3" is not allowed to own the service "org.x.config.display0" due to security policies in the configuration file) (II) config/hal: Adding input device ImPS/2 Generic Wheel Mouse One other problem I have with that kernel is that my USB wireless LAN card isn't seen, even though I have the correct prism54 module set in the kernel, like in my new kernels where it works fine. By the way, if you choose prism54 built-in, for some reason the kernel stops early in the boot process for several minutes before continuing. Should I file a bug? Do you have an xorg.conf? I've been doing this without one, which works with the other kernels.