This guy might be able to satisfy you, but you better get your loot out:
http://midwesternmodelworks.com/
Simon
Though this is super impressive, i would like the models in plastic so the individual can add their own details if they liked. Not everyone can drop $2000 on a super nice model, including me. Thanks for the link..
If you are a modern era modeler, you will be disappointed in accurate O scale models Anthony.
Even for steam and transition era modelers O scale lags HO (and N) in accurate RTR scale plastic models.
One can't blame the manufacturers. Sunset/3rd Rail (similar to Kato in fidelity) annouced the SD40-2 and received abysmal reservations. It wasn't Midwest Model Works fidelity nor was it MMW price. It would have been much like Kato has offered in N and HO but had relatively few takers. Much of the current line of EMD and GE diesels (ACEs and ES's) have been done in O scale but are mostly 3 rail and certainly not up to the level of fidelity you are used to in HO.
O scale, which traditionally required more space and more money for mainline modeling, was (is) geared to an older crowd (like me) who favored steam and first generation diesels. Somewhat different from N and HO which certainly attracts steam era but has a much larger following of modern equipment.
P:48 is a completely different subject. There are few RTR locomotives and even fewer steam though there are an increasing supply of conversion wheelsets for diesels. There is also plans to offer P:48 wheelsets for current run Sunset/3rd Rail diesels which will open up a huge market. Again, that helps if you want F units or SD7/9's or Kraus-Maffeis but not so good for SD70s.
And there is code 148 and 125 P:48 flex track but no ready to lay "snap track" style turnouts or crossings. A double edge sword, since we have no "snap track" turnouts but we do have a company that offers a line of turnout components that allow you to build ones that have all of the pieces of the real ones (accurate tie plates and fishplates, stock rail braces, manganese frog inserts, etc).
"Scale modeling" can certainly be done in O scale or P:48 but it is a much larger undertaking if you are used to things like HO scale diesels with Cannon cabs and tons of road-specific add-on brass details. In general they just don't exist in O due to a lack of interest.
This will change as more younger folks come in and start wanting SD70s, centerbeam cars and ethanol tankers instead of E and F units.
All of this is just my opinion but I try and be objective about my observations. FWIW I model the 1940's PRR and it's just as difficult to model it accurately in O/P:48 as if I were modeling today's UP/BNSF/NS.
Oh, if you search a bit on here you can find a fellow from France that was disappointed in the lack of modern diesels in O scale... so he decided to draw up 3d drawings of a modern EMD SD and have it slowly and methodically printed in shapeways as to build an accurate O scale model.