I’m in camp “arrows on hjkl on a layer, home/pgdn/pgup/end right below that”, but if you really want them as physical keys, I’d probably stuff them below the pinky cluster, right next to the outer thumb.
That, or maybe something dpad-like on the left edge, close to the H.
Edit: Oh, for clarification: I’m a programmer, as well. I make plenty of use of the arrow keys, so it’s not like “eh, let’s stuff those on a layer, I never use 'em anyway” or something.