Windows 8 installed successfully.
In a nutshell -
The external DVD drive is the problem.
After alot of reading, I decided Windows Installation wasn't recognizing the external DVD drive.
So I went through the annoying task of removing a HDD and replacing the DVD drive in the original location.
Startup + ALT, boot to Windows Disk, and BOOM!!! It worked. Completed whole Windows Installation flawlessly.
Made sure it worked properly, then turned off computer, removed DVD drive, reinserted spare 500gb HDD, and everything was back to normal, but with Windows installed.
If you don't know how to replace your DVD drive, you can check out a good walkthrough here
Hope this info helps someone out there!!