I just stumbled across this discussion. I hope I'm not too late.
As to up and over in 4x6. I do not recall a up and over for two trains in that space. Atlas has one for one train. Yet, there are plenty of flat plans that could be made to go up and over despite that issue. In such a small space you may want to use cookie cutter benchwork to get your up and over.
The gateway nmra group has some nice layouts they've built. although not up and overs on the smaller ones they are worth visting.
Atlasrr.com has a trackplan section with sample layouts.
google Ho scale trackplans and see what comes up too.
Keep yer countin' to your own damn rivets!