Not looking forward to it since I imagine these will be reminiscent of coffee rather than indistinguishable. But then if coffee is going to be that expensive, substitutes don't need to be as good as coffee, just more appealing than tea.
I tried to substitute tea for coffee a while back because the coffee I was drinking was giving me really bad anxiety in the mornings, but the higher caffeine teas were honestly just as bad or worse, and the tannin content would have me all jittery. I think I'm particularly sensitive to tannins, though. I couldn't really ever find a tea that was a good balance between enough caffeine and low tannin content, while switching from a blonde roast to dark roast pretty much solved my issues with coffee...