Sorry for reviving this thread from the dead, but I did spend a fair amount of time finding physically similar monitors with 60 Hz and 144Hz refresh rates, and as I did not find much concrete info in the internet, I thought maybe someone else can benefit from my research.
I settled for the following monitor combo: AOC G2460PG (144 Hz G-Sync) and AOC E2460PDA (60 Hz). Both monitors have basically identical frames with the same panel size, same faux-metal plastic finish, same design for the back and the stand. The G2460PG is slightly thicker, but this does not show from the front. The main difference is the green line below the panel on the G2450PG, and the G-Sync branding both on the front and the back. But otherwise the monitors are basically identical.
It is worth noting that the color calibration is not the same on both monitors, so a fair amount of fiddling is necessary in order to have a similar tint on both monitors. I did not manage to get both monitors to have an identical color response, but it is close enough for my needs and I don't notice the difference unless I actively look for it.