Toyota's first hydrogen car hasn't even gone on sale yet here in the US, and already we're hearing rumors about a follow-up vehicle. According to the Australian website Motoring, the Japanese auto giant is planning on taking the same fuel cell system it used in its mid-range Mirai sedan, and putting it into a higher-end Lexus LS limousine. For the most part, then, the new vehicle will make use of the same technology, though Toyota will apparently have to do some retro-fitting in order to make it work inside the current Lexus LS. (Unlike the LS, the Mirai was built from scratch as a hydrogen car.) If Motoring's report is correct, the new Lexus will have a fuel cell under the front seat, with the hydrogen tanks located behind the rear seat. Also, despite the fact that the LS wasn't originally designed as a hydrogen vehicle, it will reportedly offer nearly the same range as Toyota's existing FCEV: 239 miles, versus 300 on the Mirai. No word yet on price or whether this report is even true. And we suspect it could be a while before anyone sets the record straight -- the hydrogen-fueled Lexus LS is rumored to launch "by 2017," up to two years from now.