Funny part is that Intex doesn't seem to have a Qualcomm based phone ATM, so speculating around what existing phone it might be based doesn't seem to have much meat around the bones.

Judging from the quick flash on Saarnio interview, it does look like being based on Jolla's reference design rather than any existing Intex design, if the prototype device was not "camouflaged" in some way (which I doubt). The screen captures in reviewjolla-page show these details:





...which resemble the mock up pics shown in suomimobiili and some other sites, and reference platforms that were shown in MWC 2015. The same "sandwitch"-design, but maybe a little slimmer.

Another possibility of course is that the prototype device was completely different from upcoming phone or phones. But I doubt it...