Installation stuck at grey boot screen on Macbook Pro 4,1 (Early 2008)
I'd do a quick triage to boot the Mac into single user mode to see if the boot drive / base OS is minimally functional. After that, I'd start with systematically working through the startup troubleshooting guide from Apple.


OS X: Gray screen appears during startup  - http://support.apple.com/kb/TS2570


You've clearly done many of the steps, but the order of steps is very helpful in knowing what the likely cause of the problem is. I might skip removing the SSD if you don't have a HDD - but installing a clean OS onto an external HD at that point might be a good way to rule in or out your SSD as contributing to the failure to install and boot properly.