I've always used rxvt-native program on cygwin. I installed the 64 bit cygwin and I cannot find an rxvt package in there. I installed the 32 bit cygwin of the same version and it seems it's still there.
Anyone have any ideas why this package would not be available for 64bit installations of cygwin? and any way to get it?
Many 32-bit packages have not yet been ported to 64-bit, for various reasons. The most common is that the maintainer just hasn't had time, or may not have access to a 64-bit Cygwin environment. Often a new maintainer is needed.
You can find the complete list here. Yes, rxvt is on it.