Wayne -
Appreciate the comments / thoughts...
With this morning's coffee - I came up with a couple more "possibilities" - and also changed out the overpass on the #3 English Curve with a cross over to see how it looked (I like the "flat" nature of that!)
So here are a couple more for viewing pleasure and for me to mull over....
Design 3 - English Curve - WITH the crossover added to make it "flat"

Now the "new" additions...
Design 5 - Bent Paper Clip
(advantage - should be smooth fast track - but may not offer enough "challenge"?)

Design 6 - Mountain Pass
(advantage - mix of high speed with variety of curve types)

Design 7 - Mountain Canyon
(advantage - mix of high speed with even more varied corners / twisties)

Design 8 - Mr. Twister
(advantage - mix of corner types in both clockwise and counter clockwise)

On a side note - this Ultimate Racer 3.0 is a pretty darn handy tool for making up these various designs when you don't have the track pieces available to try it out live! You can input the pieces you currently have in the "track inventory" and as you flip through the different designs that you make - it will show you what pieces are used for the design, how many of those you have on hand and how many extra / additional you may have/need! VERY handy!!!
Definitely two thumbs up for the designers!
:D