I dont know how big your area is, we have a small-ish hall at Caldicot but we have a excellent track designer in Blue_Pinky, and other experienced drivers that help out designing or 'tweaking' when needed.
I notice you said wall-of-death... thats one of Caldicots most requested track features
http://www.youtube.com/watch?v=capEBMwLqDk
When you get it right and have the balls to keep the throttle planted at 100%, it is ace to run
We have lost the odd car over the back though.. including one of mine
But Roger is completely right, too many 'features' slow down the flow too much. Marshalling space is also important - great having a track that uses all the available space, but if you turn over in the middle and a marshal has to run over two or more lanes/features to get to you, you can lose 10 seconds or more whilst he/she waits for traffic to pass so they can get to you.... that's effectively the end of your qualy run for that heat.
Experiment a bit though, but start simple-ish and work up, rather than the other way round.
Good luck, and remember to take some pics of good tracks and keep a file of them & their plans like we do