I'm right into NG 3ft - 36" gauge stuff. I've got most of whats available. (There's a reasonable amount of both loco's & wagons). Unfortunately in my searching for 3ft stuff, I haven't come across much 1000mm content.
Maybe worth considering changing from 1000mm to 3ft -36" gauge because of the extra 36" content...
DLS; Put 1000mm in the Text Search. The "dot" in Description & tick all Trainz versions on the DLS (including 2004). That will show you how little 1000mm stuff is on the DLS...
Cheers, Mac...