Hello From NYC

Nycnec,Welcome to the board! It was hoped by now,Walters would have done a new run of the Comet/Horizon Fleet cars by now.
That "Gulliver's Gate" project looks to be a massive undertaking. Good Luck on that project.
You might find some "M-series" kits at Island Model Works.
FYI: there's no such "thing" as a finished Model Railroad,there will always be maintaince and "tinkering"
with scenes to "improve" the final outcome.

Should have went HO, we're working on an NEC modular club. Still, there are a lot of nice 3D print options in N scale lately!

Unfortunately, if Gulliver's Gate is dead set on having a big "Metro North" fleet, they're probably going to have to build it themselves. On top of the Walthers cars being difficult to come by, most of the existing Commuter car models are going to take work. As backshophoss noted, the only HO M7 is going to be Island Model Works.

These kits aren't always perfect. Sometimes you'll get one that is fine, other times you can tell the mold experienced shrinkage, and either the body shell or the floor is too small. IMW kits can be made into nice models, but they are often crude if completed "as is". It can take a lot of extra work to refine them.

Again, they can be made into nice models, its just that they take a lot of work.

Its going to be a challenge modeling New York's Commuter railroads. Pretty much nothing is RTR, and most of it that is are stand-ins (P40DCs for P32ACDMS, Comets for Shoreliners, etc).

We have a Yahoo group at Heavy electric Modules. I'm not sure if anyone started a facebook page or something. We will be down at the Timmonium, MD trainshow this weekend.