Marat is at the BLIS Retreat, and just gave a presentation on Peach-Py, his Python-based assembler. Peach-Py gives you the control and efficiency of assembly programming with the convenience and ease of Python syntax, while also automating key tasks like constant and register allocation. Peach-Py currently supports a variety of x86 and ARM instruction sets.
If you missed his talk, you can see the PDF slides (and eventually the video) here: PDF [357 KiB]
Incidentally, BLIS is an exciting new effort to build a new infrastructure for high-performance primitives.