So Clamshell Android phones are a thing. The Freetel Mushashi is a T9-style Android phone with dual touch screens on either side.
Samsung has the Android W series phones which have a similar format.
Regarding the sibling comment, after the Droid 4 and the Motorola Photon Q, there has been a drought of physical keyboard landscape slider phones. Portrait sliders have been available for the Blackberry Priv and KeyOne/Key2, but aside from the soon-to-be-released Fxtec Pro1, not much landscape slider android phone action is going on.
last mainstream device i can recall in this form factor was the droid 2? I think it's been a while since a major one was released, but I could be wrong.
Samsung has the Android W series phones which have a similar format.
Regarding the sibling comment, after the Droid 4 and the Motorola Photon Q, there has been a drought of physical keyboard landscape slider phones. Portrait sliders have been available for the Blackberry Priv and KeyOne/Key2, but aside from the soon-to-be-released Fxtec Pro1, not much landscape slider android phone action is going on.