Todtnau Bike Park sits only an hours drive from Basel on the German, French and Swiss borders, and has been used for iXS events for a few years now. The single 2-person chairlift has special bike hangers that takes 2 bikes hung via the saddles, and you get on the chair that comes behind it. Looks slightly precarious but works well.
The DH trail is an awesome course! It has everything – steep technical sections, fast sections, berms, jumps, drops, and famously if you have seen the pictures from the race events here, big big roots. There is only the one other trail to the DH track (which by the way is just called “Downhill”) – a blue marked trail called “Wildride”. This is a fun track without the steepness and tightness of the DH. It’s what you would expect a blue to be, with a couple of fire road sections, and it’s a good roll as a warm up for the DH.