Okay Arnold, you are the unofficial ( and perhaps you should be the " official") OGR Forum philosopher!! Yet again another phenomenal topic you've come up with!
Now I'm going to take your suggestion and dream BIG! In the examples you gave for dreaming big, you mentioned the word " structure" which I took to mean model structure. My BIG dream is to have a real stand alone structure around 80 ft x 50 ft. built in my back yard. This structure would house primarily my train layout on the main floor with a loft overlooking the layout for my music studio. Of course I'd build the layout in the shape of the letter "E" with all edges rounded. The back of the E ( spine ), set against the wall of the building would be 60 ft. in length and 10 ft wide and include pop up hatches for access. The outer protrusions of the" E " would extend forward 20 ft with a 8 ft width with a large city built on each outer protrusion. One of these protrusions would host a seaport with docks, cranes, ships, tug boats, barges, etc. in addition to the large city.
The middle protrusion would also extend forward 30 ft with a width of 8 ft. This section would host my home town, of Savage, Maryland. Lots of history in this town! The old cotton mill dates back to 1820 and was served by the B&O thru the 1960's. The first iron railroad bridge system used by an American railroad still spans the river to this day. The rock quarries nearby were also served by the B&O's Patuxent Branch line which came off the B&O's Washington Division. I'd have a master modeler build a detailed model of the cotton mill, it's steam powered powerhouse ( served with open hopper cars of coal pulled to the power house by an electric winch ) and hydro power house, and the horse race track nearby. In addition to the mill the master modeler would build detailed models of the community hall which was constructed of stone hauled out of the nearby river, the elementary school, the mill mangers ornate home, the company town houses, the churches, and first fire house. Another cool fact about my hometown is that once the cotton mill closed in the late 1940's it was purchased by a Christmas Ornament manufacturing company. The mill and all of its' mill homes were decorated/painted in Christmas colors and a reindeer castle was built. Christmas music was played over speakers throughout the town and B&O passenger excursions brought thousands of visitors to my hometown to have a wonderful Christmas experience. I would also model this.
Between the large cities along the spine of the "E" would be small towns, villages, and hamlets, all with their own individual charm. One town's station would be a model of the old B&O station in Ellicott City, Md. which was the fist railroad terminus in the U.S. It still stands today.
There would large freight yards at each city and passenger coach yards. Stub end passenger terminals ( one replicating B&O's Baltimore's Camden Station ... now Camden Yards where the Orioles play and the other station would be a model of Western Maryland's Hillen Station in Baltimore ). There would be round houses at each city with working turn tables.
A detailed model of The Thomas Viaduct Bridge will exist on this layout. This bridge, about a 15 minute drive from my house, was the first part of the B&O's Washington Division which spanned the Patapsco River built around 1835 ... and still carries CSX and MARC trains to this very day.
Of course Lionel, MTH, K line, operation accessories ... as much as possible.
The layout would run on multi levels ( with all levels connected to each other ) and include all the railroads of postwar Maryland ( 8 in all including short lines ) Each railroad having its' own level or area on the main level so these railroads could run on the layout simultaneously.
All of this set in my favorite era of railroad history ... the transition era. ALL SCALE EQUIPMENT ... Locomotives of the B&O would include ... 3rd Rail B&O EM 1, Presidential class Pacifics, the Cincinattian, Mikados, Dockside, all first generation diesels. Sunset Models Capitol Limited complete set. ...... Western Maryland Challengers, K2 Pacifics, BL2 #81 & 82, Shays, and first generation diesels. .... Pennsy GG1's, P5a and P5a modified, 2 - 10 - 4 steam locomotives, K4 Pacific, MU cars, and first generation diesels. A Sunset Models Broadway Limited complete set. ... Norfolk and Western's Jawn Henry by 3rd Rail, J class 4-8-4 both with streamlining and without, 4-8-0 Mastadon, Class A mallets, Y6b mallets.
Special custom build loco: B&O's steeple cab electric that ran on the Baltimore Belt Line from Camden Station to Roseville, Md.
All track Ross Custom with Ross Custom switchers. Lionel Legacy and MTH DCS operating systems.
The joy would come from running the trains, of course, but even more so in sharing this layout with family, friends, and folks in my community!
Well I've got to go to bed now and hopefully dream BIG!!! Thanks for this opportunity Arnold!
In fact, I have found myself selling a few items for continuing construction of my 
