This article doesn't directly answer your question but it addresses some of the challenges. The supply and quality are likely there. Most are predicting a healthy run from formations above it before going that deep though. Maybe a good indicator of timeframe will be when depth restriction clauses become obsolete.
In North Central PA and across the state line in NY the Trenton/Black River was in play prior to the Marcellus Shale Phenomenon. There are/were a good number of TBR wells that produced good numbers. The downside to these wells were the shelf life of production and the hit or miss nature of drilling the formation. Drillers had to hit the feature correctly or the investment was lost. As it was described to me the TBR is pocket gas as apposed to an entire layer that could be fracked. The driller had to his the pocket. When conditions were right the production from good wells was outstanding initially but would drop off significantly in the first year.
That said, the TBR feature could be completely different in other areas just like the Utica is proving to be.
It's not really economic to produce right now. The formation is a lot deeper than the Utica, making the technology more expensive. The formation is unproven, but has promise. Since there's a lot of risk and cost involved, it's going to take much higher prices to attract investment. It'll happen, just not right away.
I noticed RRC on those few (3) utica are drilling into trenton on at least 2 wells. I assume for core samples. Trenton isn't that much deeper than Utica in RRC territory. RRC not going to spend $$$ on Utica for years. Too much to get out of Marcellus and UD.
I'm in SW Washington County, PA. RRC territory. Near I 70 and WV state line. Yes they do have UD wells. They are more of a test than development. The quote from RRC was "Marcellus is low risk high return". My translation: right now marcellus is easy money so why develop other formations. That is especially true at $3 gas.
I also believe Marcellus is more uniform than UD. UD will have different targets and fracking procedures. Utica is even more uniform than Marcellus. RRC says Utica wells cost 2.5X more than marcellus wells. How many Marcellus wells has RRC drilled? 100X? their Utica numbers (3). Just a question of getting experience on Utica wells.
Experience also applies to UD. But I think oil price is bigger factor. Depending on which UD is the target. Burket is close to marcellus content. Burket is thin in my area. I also think Middlesex is absent in my area. I'm much more confident about Rhinestreet. I won't go into "local" geology and argue about that odd well RRC has on our Unit pad.