Yup, that would be a nice plugin though I dunno how much work would it need for PC.
http://ngemu.com/threads/new-standard-in-gpu-accuracy.143888/
http://ngemu.com/threads/new-standard-in-gpu-accuracy.143888/
It can be adapted from what's in PCSX-ReARMed,
but I don't know how much work that is.. you can browse it here:
http://notaz.gp2x.de/cgi-bin/gitweb.cgi?p=pcsx_rearmed.git;a=tree;f=plugins/gpu_neon;h=c699398db2c2871d974ecfc7324908c1a0f9ebae;hb=652c6b8b676be0172612da811b38dd5f87fa2870
It's currently using psx_gpu.c when you'd probably want it to use psx_gpu_standard.c.
psx_gpu.c works but it's probably a lot slower, since it was prototype code
for the vectorized NEON version. On the other hand, I haven't
tested psx_gpu_standard.c in forever.