Having never used Spektrum gear I'm not 100% familiar with their programming/operation, but with the difficulty in obtaining bot receivers for them, could the DX6s theoretically be fitted with conversion/hack modules? Obviously they're already on 2.4GHz but if the PPM-equivalent line can have the module soldered on, that would open up the possibility of continued usage of the DX6s through the likes of Corona and FrSky (the FrSky receivers in particular are incredibly easy when it comes to setting failsafes on all channels).