I filed Bug#917546 (binutils-xtensa-lx106) and Bug#917547 (gcc-xtensa-lx106) this week and both packages are now sitting in NEW. They target only the lx106 (ESP8266) Xtensa variant, but will hopefully be useful to others. I think this RFP should remain open, as long term it would be good to have a single Xtensa toolchain that is runtime configurable for multiple platforms.
J. -- "Scattered f***ing showers my ass." -- Noah