Nice, I hadn't seen the polyend mess, but that looks good too. And there's the Meris Enzo X (currently £539 at Andertons). No sample triggering with either of them though.
The Meris and Quimera include a tuner (not sure if the Polyend does) and some more normal effects so perhaps could be used as a stand-alone multi fx pedal?....and a decent bass triggered synth, and a midi controlled keyboard synth.
£500 is a lot, but if it is a decent multi fx, bass synth, midi synth, equivalent to things that are about £200 each then I could convince myself when things like the MXR Bass synth, C4, FI alone are about £250, and a lot of the relatively budget multi fx are about £250.