3M makes the material, StonGard has them also, sometimes cheaper. www.stongard.com. If you're handy with a knife you could possibly purchase the material then cut and fit it yourself.
I've had these on since...oh...spring of 2003? or so, they're holding up ok. Not sure how well they work since I've not had a cracked headlight/foglight yet. The fogs have some heavy indentations, so I'm guessing I've had a few close calls. I don't see any cut in the amount of light, though I didn't do a "before and after". Put them on my wife's Volvo, no problems their either (if you think the BMW lenses are $$, the volvo cover is up near 300.00 or so).