[tptacek]

Not so much: http://cr.yp.to/qhasm.html

The version of our Ruby x86 assembler on my desk does register allocation as well.

[jwr]

Cool! This is exactly what I had in mind. I didn't know about this project.

Unfortunately, it seems to have been abandoned...

[tptacek]

It's not abandoned; DJB continues to use it in his crypto papers. But it's not really a standalone project yet.