I also recently made an adapter for my L2 charging station (mines a Siemens with plug). 14-x0P to 6-50R but I did it inside the plug instead of a[nother] cable. I'll only post a couple pics here but you can see the rest here:
http://s60.beta.photobucket.com/user/1234567890_a/library/Outlet Adapter
I had to do a lot of cutting to get it to fit the way i wanted it to... I'm talking hours because I took my time and there's plenty to cut, even then its still not great- I ended up cutting and heating the hook on the end just to get the thing together. Obviously this shouldn't be used on 'anything' as it allows you to plug a 50A [something] into a lower amp outlet, who knows what wiring is behind that outlet, could be 6 gauge, prob isn't... That being said, the Seimens unit allows me to select what current i want to limit it to, 25%, 50%, 75% or 100% of the max (30A). So i can easily limit draw to whatever outlet is available...]