update (2014): Others have had luck in using the most current (13.10) ubuntu installer directly, so you should try that out before going this more complex and error prone route.
After many false starts and pain I found a way to boot linux on my aspire which doesn't miss any of the functionality. I have not got things coexisting with windows 8, but I can live with that. I happened to have a usb stick with ubuntu 12.10 installed sitting on my desk. Start it in try before you buy mode. The first step is to back up your windows partitions. I did this using a back hard disk mounted at /media/ubuntu/1234etc with dd if=/dev/sda of=/media/ubuntu/1234etc/laptopwindows8sda, dd if=/dev/sdb of=/media/ubuntu/1234etc/laptopwindows8sdb. I got an amazing 150MB/s write to a spindle disk using this! I have restored from this without trouble.
I am booting using the legacy boot mode. After spending a long time trying to get uefi booting to work before I discovered the problem was the raid controller, but I am loath to switch back to uefi. People have warned me that others have had really bad experiences with uefi with current builds, so I'm going to leave that one until others have walked the path. So legacy boot system. I could not get the bootloader to be found with the raid turned on, so I've switched to software raid, which is a little heavier weight power/cpu wise. But it works (touch wood).
So I've made both ssds have the following:
- 200MB ext2 boot
- 4000MB swap
- the remainder being used as raid 0
To turn on the software raid:
mdadm --create --verbose /dev/md0 -n2 --level=0 /dev/sda1 /dev/sdb2
I initially put --level=1 here but someone contacted me to confirm. It should have been level 0 (128GB total, no redundancy).
Put a file system (I couldn't get the installer to create a file system directly on md0):
Then use the built in installer with the 'other' option to select the md0 mounted as /, /dev/sda1 as biosboot (although I don't think this is actually needed), /dev/sdb1 as /boot. It automagically found the swap partitions.
After this the system would boot the kernel, but not mount /. To fix this I came back into the installer (try without install) and remounted target (and /target/boot /target/dev /target/dev/pts /target/sys /target/proc /target/run) and chrooted in. It also helps to cp /etc/resolv.conf /target/etc/resolv.conf so that you have internet in the target chroot. Then I updated and upgraded the apt. Then make sure you install mdadm in the target. This will rebuild the initrdfs so that it has the appropriate module for mounting /dev/md0. Finally, I recommend if you have the space just dd if=/dev/sda of=/backup/laptopsda and similarly for /dev/sdb so that you can quickly restore.
I imagine this would work on all the related models. (S7 391-6810 and S7 391-9886)