If you updated to 10.5.5 and lost your GMA950's internal display, follow these steps and I guarantee that you will have it working again!
1. You will need to have your previous working kexts and OpenGL.framework. You can extract them from your install DVD or .iso with Pacifist.
2. Install your kexts with OSx86Tools or Kext Helper. Install OpenGL.framework by removing it from /System/Library/Frameworks, then put the old one in.
3. Open Disk Utility, select your startup volume, select the First Aid tab, then click Repair Permissions. Now take a coffee and wait
4. Pray and reboot.
5. If you did it right, you should see your desktop coming up!

This fix has issues with certain hardware, Restart, About this Mac and System Profiler seem to break.

I believe the proper fix is to know what is being modified in the AppleIntelIntegreatedFramebuffer.kext and related software and then move those patches forward to the newer versions.

Of course this doesn't guarantee that things wont break but the chances of breakage will be significantly lower.

Another plausible solution is to find out what is being modified and see if this cannot be overcome through the use of a kext thus alleviating the need to modify the files.

Diabolik had a GMA950/GMAX3100 Natit/Alkor driver that he stopped supporting and I also believe that this might be a better solution however, along with dropping support he wont allow anyone else to pick it up because he wont release the source code so everyone is stuck waiting for some magician to fix things up so graphics works properly again.

Now you can see how the contributors to the community are also the ones preventing and controlling progress.

I'm kind of curious here...
I went through this step by step several times ( I have a desktop with an Intel GMA950 - ID 2582 that currently isn't working with QE, though it was with 10.5.4 )
I've gone through, re-installed the previous working kexts and installed the older OpenGL.framework... after restarting, I can see no change... except if I go into System Profiler, and check Frameworks... there's no version listed with the OpenGL.Framework...
Shows up as such :

Last Modified: 14/10/08 4:40 PM
Location: /System/Library/Frameworks/OpenGL.framework
Private: No

I've tried several different methods of reverting to the older OpenGL.framework ( from what I see, and what I know... it will allow me QE support... which is kind of nice ) and it always shows up the same. Of course, I never checked it beforehand, so I don't know if this is different than before. ( And yes, I've repaired permissions, several times )

Any suggestions on the cause/solution for this one?

I realize this thread is older than dirt, but just wondered if that meant everyone figured it out, since I am having the same issues with reverting to 10.5.4 OpenGL framework in 10.5.5. Anything?