I think the only one that can take 2 full-size drives without swapping out the optical bay is the G771.
EDIT: You beat me to it. Yes, the G771 does support 2 drives. No it isn't better when compared to the G751 in any way that matters, I think. Also the cooling is definitely worse. These odd number G-series machines have tended to be recolors of the N-series entertainment laptops. Not specific gaming designs like the G751.
The numlock thing is a bit annoying but I've been using the laptop since December and I've turned off numlock maybe twice.
It's a not a frequently used key these days. I found the Steam key more annoying but that's fixable so it shows the normal desktop view of Steam.
It's funny that it also turns the laptop on and then loads steam if you press it when it's shut down.
I repeat that MINE sounds great to me and I've heard a few here in Bulgaria and they pretty much sound the same as mine. Again, i didn't have the issues other people had on this forum at the time that they had them.
Keep in mind that the SATA bay where the M.2 connector is also housed is the SATA3 one...the other one only supports SATA2. However, it is possible to stuff a 2.5 inch SSD and a M.2 SSD in the same space by opening up the 2.5 inch SSD and putting just the board in.
Also, don't expect stellar customer support from ASUS...or any laptop company, really. Me and a few others were lucky but many don't want anything to do with these companies. I buy ASUS for the hardware.
Here's the G771's internals. Funny how some of the parts say N751 on them etc.