I've got a friend who wants to rock some O and he tried on several pair this weekend. His favorite was the Half Wire 2.0, but he felt like the were a bit too tight from ear to ear and would get uncomfortable after wearing them for a while. Can anyone recommend a similar model (preferably a wire) that would better suit his wide head?

How about a Half X or the XL Half Wires.

Half Wire 2.0's have a pretty decent size to them, first thing that pops into my head would be the Nano 3.0's because of the light fitting arms. He should also try the new Square Wire or the Splinter as they both have spring hinges but the fit will more than likely be very similar to the Half Wire. It seems that most styles will have a very similar head fit from arm to arm its more of the orbitals that change.
Another option is getting a fixed hinge pair (Whisker, Square Whisker) and having an experienced optical person (O Employee or Optician) flex and specifically fit them for him. I have found that to be successful for the larger domed customers I have encountered.
Im not sure I'm familiar with an XL Half Wire 2.0, and the XL Half Wire is much smaller. Also the Half X seems to be a better fit for mid sized heads, the gasket hinge system doesn't feel like it opens up as much as the full spring hinge on the Half Wire 2.0's

Good luck on the hunt!

I originally thought about the New Square Wire as well. Then I was looking around and saw the Half Wire XL, but from what I can tell the only XL thing about them is the lens size. Someone correct me if I'm wrong.

Bob...pretty sure it's a bigger frame too.

I originally thought about the New Square Wire as well. Then I was looking around and saw the Half Wire XL, but from what I can tell the only XL thing about them is the lens size. Someone correct me if I'm wrong.

In the past it's only ever been a lens difference. But I say Splinter as well, they are huge compared to older wires.