Hi Nick,
Regarding the downwind bit.
Sure, no problems landing or taking off. Like SASLESS I have done bazillions of them as it is rare to get a nice wind on the nose in day to day off field operations.
I distictly remember a 20kt downwind at night in to Simcoe cone site. What a giggle that wasn't.
But the question remains how to cope with the increased personal risk with an engine failure (here we go again!
at say...40ft on takeoff.
In a single, where is the room for the flare to clear the tail?
In a twin, you are now behind the curve and struggling for that clearance from the rig, hospital, trees....
You are just making life very difficult for yourself.
The other issue I have noted, is that you tend to get "blown" off the bubble while doing a downwind departure. That is not a very technical term but I think you relate. This is assuming a nice level disc attitude and 6ft hover (as Shawn so excellently exposed out of the Bell 206 manual a couple of years ago.)
The aircraft settles and if over unhappy terrain that is an uncomfortable feeling requiring more power to stop the decent.
This is all assuming you have the option for an into wind departure and the downwind is a choice rather than a requirement.
Cheers for the thoughts. <)