It is strange that you cant boot into Single User Mode using -s If you can't boot into Single User Mode you may have other problems. You can give it a try if you like but you may end up making the problem worse. I highly recommend doing steps 4 & 5 and also keep a note of the kexts you remove as you may wish to restore them.
You can boot your Install DVD and modify them via Terminal. When you get into the installer choose Terminal from the tool bar.
1. We need to find the volume OSX is installed on. For example I labeled mine "Leopard" If your not 100% sure you can check by typing:
2. Now we can change directories to your volume's /System/Library folder (Replace "Leopard" with the name of your OSX volume)
Code:
cd /Volumes/Leopard/System/Library
3. Now lets get a list of those kexts
4. Lets make a backup copy of your extensions folder just in case you need to restore some files. First make a folder to save them in. Well call it backup.
5. Now lets copy the contents of your Extensions folder to your backup folder. (Highly recommend you do this)
Code:
cp -r Extensions/ /Backup/Extensions
6. Now we can do some editing. If you see a kext you want to remove then you can use (Replace PROBLEM.kext with the one you want to remove)
Code:
rm -Rf Extensions/PROBLEM.kext
Repeat this step for the kexts you want to remove.
7. Now that we are finished removing we want to delete the extensions cache to force OSX to rebuild it with the ones you just removed.
Code:
rm -rf Extensions.mkext
Now reboot with -v -f
[EDIT] If you want to restore one of these kexts do the same as above but replace Step 6 with the below (replacing KEXTTORESTORE with the one you want to restore.
6a. Copy the kext from your backup folder to your Extensions folder
Code:
cp -r /Backup/KEXTTORESTORE.kext Extensions/KEXTTORESTORE.kext
Repeat this step for each additional kext you need to restore.
6b. Correct permissions for our extensions folder.
Code:
chmod -R 755 Extensions/
6c. Correct ownership for our extensions folder.
Code:
chown -R root:wheel Extensions/
6d. Touch the extensions folder
Continue with Step 7 from above.