I have done this layou for test purposes, maybe i will improve it on summer holidays =)

Some screenshots:
http://imageshack.us/photo/my-images/19/imagen1sb.jpg/
http://imageshack.us/photo/my-images/708/imagen2kk.jpg/
http://imageshack.us/photo/my-images/837/imagen3g.jpg/
http://imageshack.us/photo/my-images/96/imagen4pj.jpg/
http://imageshack.us/photo/my-images/685/imagen5gl.jpg/

The start is wrong way?

The start is exiting box to the right

Love it! please make another one thats better!!

Sorry, but i tried and it isn't this good. The layout seems nice, but the quality is quite bad. Some places are so thight that the track is halfly on grass. Dunno, it just isn't a touge

Nice effort tho