Hello. First I'd like to thank you all for giving me a starting point to figure out this problem. I'd also like to let you know how I finally got it solved.

I managed to get 10.04 x86_64 installed and working on my Core2 Quad setup, running a 2-drive striped array on Intel Matrix (fake) RAID. It took me about 8 hours of screwing around and multiple reinstalls to find a solution, even though the solution is actually quite simple.

Here is the process:

1. I found it easiest to boot the install disc into the live CD mode instead of the installer. Contrary to what has been stated in other places, you do NOT need the alternate install disc. It works fine on the regular Desktop disc.

2. When you get into the desktop environment, go ahead and start the installer, go through all the steps, set up your partitions, etc. I created a separate boot partition on my array, but I do not believe that is necessary.

3. When you get to the final step, where it gives you the "Install" button, stop and open a terminal. Pretty much everything you do in it will need root privileges, so go ahead and issue the "sudo -i" command.

4. As has been stated, the installer needs to see /dev/mapper/array_nameN (where array_name is the name the system assigns to your RAID, and N is the partition number) instead of /dev/mapper/array_namepN. So you'll have to cd to /dev/mapper and get those devices in there. I was a little nervous about renaming them, so I just added some symbolic links for all of the partitions. Use "ln -s array_namepN array_nameN" for each partition.

5. As has also been stated, you need to hit the "Advanced" button in the installer and point it to set up GRUB on your array's MBR (note that it should be the name of your array, not one of the partitions). Then go ahead and hit Install. Leave your terminal open, as you will need it again.

6. When installation completes, don't reboot yet. Go back to your terminal. The new install partition will be mounted in /target, but if you made a separate boot partition, it will have been unmounted, so you'll have to re-mount it by issuing "mount /dev/mapper/array_nameN /target/boot". If you didn't make a separate boot partition, you obviously won't have to do this.

7. Issue the following commands to set your terminal's environment to use the new filesystem:
mount --bind /dev /target/dev
mount -t proc /proc /target/proc
mount -t sysfs /sys /target/sys
cp /etc/resolv.conf /target/etc/resolv.conf
chroot /target

8. Run "update-grub" for good measure (not sure if it's really necessary). And here's the key to making this all work: run "apt-get install dmraid". I had assumed that this would already be installed by default because of the many people who use it, but apparently not. Installing this package will update your initrd image with the correct modules to run your fakeraid, and it works fine with GRUB2, even though some people have said you need to install GRUB1.

9. Exit out and reboot into your freshly installed Ubuntu!

Another option that might be easier would be to make your boot partition on a non-RAID drive, but as I don't have any non-RAID drives in my desktop, I wanted to find a solution that didn't require doing that. I knew there had to be one.

I hope this helps people out so they don't have to get as frustrated as I did.