My humble offerings to the inquiry...just build a simple 3'x4' frame on casters or wheels, so it can slide under a bed...use of a basement or room corner is better...toss some track on that in a copy, or close, of the origonal and "play". I would suggest the use of switches fired via the dynamis, but you might be able to make/find something to make regular switches work{arduino?} via DCC, then your only worries are coupling/uncoupling and trying it out.
If you like what you have- regroup and solidify everything to permanent..if not tweek till your happy.
That's the only problem with On30 is the lack of DCC coupler control for a layout as described...alot of switching...but I'm sure you could work the dynamis, some switch toggles and some coupler magnets via switches together...can't be much harder than running a magazine....you seem the multitasking type.
BTW- if this works we expect a full article about it!...no pressure. 
That's pretty much what I think I'm going to do, but with a 5' or 6' long by 36" deep board. I may order some Mianne benchwork components for a foundation and stain the pieces to match my bedroom furniture. I will probably venture over to Lowe's this weekend to get the plywood and have it cut to size. Wish I had a shop of my own (and the tools) for doing some woodworking.
