I am learning that my right knee likes a low Q factor on the road bike with both feet strait. I do get more knee pain on the mountain bike which typically have a higher Q factor. I would like to get a phat bike but I see those have the biggest Q factor of all, my knee hurts just by looking at the bottom bracket of those.

So my question is, how do you get a narrow Q body on a wide Q bike? There has got to be a way!

Is Q factor still a thing? I thought low profile cranks addressed that issue about 15-20 years ago. Have you measured the Q diff on your bikes? I mean, I just haven't seen a Q number in a long, long time. I'm not saying it doesn't exist, but only that manufacturing, design, and tubing have allowed a convergence of BB widths that we didn't have in the late '80s, and so I think it's probably a non-issue on modern bikes, generally speaking.

I'd look to other possible sources of your knee pain, and get a fat bike if you want one.

The bottom bracket width and chain stays will limit how narrow you can go. A fat bike needs wider chainstays to fit the wider tires.

I also had left knee pain that didn't go away until I went from triple to double cranks. I'm not positive that it was (wider) Q factor that was causing the pain but the correlation is so strong across four bikes that I felt like it had to be the cause.

90 degree old style cranks , that just barely clear the chain-stays are the lowest practical Q ..

I think you are in the realm of Quantum mechanics .. unless you start from scratch.

back in the past Hanebrink made a really big ATV tire bike the crank turned a jack shaft, the jack shaft
in turn turned a cog much further outboard to clear the tire..

so the primary drive was as narrow as you wish.. But even He is not making the ones he does now like that ..

so you are in the hire something Custom , realm if it matters enough , what it costs wont ..

if you are not aware of how these things can sort out.. other than just a regular bike.

back in the 60s a friend's dad made a Jack Shaft bike drivetrain..
there was a 3 speed hub up in the upper seat stay with a second cog on the hubshell.
one chain went from the crank up to the cog on the hub driver..

then a second chain went to the hub in the wheel, driven by the cog on the hubshell..

so it was a 6 speed ... 3 speeds in each Hub.

I appreciate the responses gentleman, but I am more focused on adapting the cleat/fit rather than changing the Q-factor.