I haven't personally looked at ME7.1.1 but I'm pretty sure the fact that the pressure variable is 16bit doesn't help you at all.
I'm not even sure that it is 16-bit
Hopefully Tony will be able to chime in and see if there is a way to tell for sure.
However, it DOES give you a bit more resolution if you want to try underscaling your MAP value (like what tuners did with load in ME7.1 in the beginning).
As i've mentioned before, you might have problems near the zero point, but there are very few places (compared to load) where absolute MAP pressure is used in ME7, so i really do think underscaling the MAP signal will be fairly easy.
If the larger MAP sensor doesn't pan out with this ECU that isn't too big of a deal for me.. I can easily just use an external boost controller instead.
My main interest in using ME7.1.1 is the larger maps and the ability to properly scale the fueling and timing maps for the load I will be running. Being stuck @ 191.25 in ME7.1 is dreadful IMO.