A public release of Brass has been released... it can assemble some rather nasty Z80 code (TASM macro-abusing code, that is!) fine. Hopefully people can start finding the parse errors, or just complain at the horrible colour scheme of the manual.

And why did nobody tell me you could access the LSB/MSB of IX/IY through IXL/IXH/IYL/IYH before?

@kwijibo: You can use a Latenite beta if you take this file then unzip this file on top of it. It is almost entirely data driven - all Z80 registers (that I knew about) and flags (likewise) are hard-coded (but not Z80 instructions).