Any chance of a 64 bit build for Windows? Do you think OptiPNG would benefit from having access to more than 4GB of RAM?
Benefit from accessing more than 4GB of RAM, probably not.
Benefit from the AMD64 architecture (e.g. the extra registers), possibly yes.
I haven't yet took the dive into making 64-bit Windows builds yet, though. Making the builds should be easy, but will incur extra testing and maintenance efforts. I will need more volunteers to help me with that.