Patrick - you could presumably run a VNC server inside your guest and connect to that, rather than the QEMU vnc client.
The problem with backporting a fix is that there's been a lot of code churn with the vnc related stuff in qemu, so to actually fix it would require some knowledge of the vnc stuff, rather than mechanical adding and removing of commits (I know, as I tried that sometime ago). The people with that knowledge are too busy pushing forward than looking back at old releases (understandably - it's more interesting).
Patrick - you could presumably run a VNC server inside your guest and connect to that, rather than the QEMU vnc client.
The problem with backporting a fix is that there's been a lot of code churn with the vnc related stuff in qemu, so to actually fix it would require some knowledge of the vnc stuff, rather than mechanical adding and removing of commits (I know, as I tried that sometime ago). The people with that knowledge are too busy pushing forward than looking back at old releases (understandably - it's more interesting).