It's not that uncommon to run one system on multiple CPUs. People swap out the CPU in their desktops, people move a drive from one laptop to another, people make bootable USB sticks, people set up a system in a chroot on a host machine and then flash a target machine with the resulting image.
Congratulations, you now need to make sure your on-launch detector is compatible with the lowest common denominator, while at the same time being able to detect modern architectures. You also now carry 10 different instances of firefox.exe to support people eventually running on Itanium, people that will open support requests and expect you to fix their abandoned platform.
For what reason, exactly ?
You want 32b x86 support: pay for it. You want <obscure architecture> support: pay for it. If you're ok with it being a fork, then maintain it.