Actually, you can buy them on Amazon (oh...well, if you're talking about the battery version...). The problem with the SafeRide was main it's poor battery life - around an hour with the stock batteries, over an hour but a little short of 2 hours (if I remember right) with the best AA batteries. It has some sort of internal timer or something so it would still turn off at 2 hours (or so) even if you rewired it to use a larger external battery pack.

Apparently last fall Phillips decided to stop selling them in the US - right at the same time that the B&M Ixon IQ Premium was announced, with similar light output (and apparently a well designed shaped beam) but with 4-5 hours of battery life -
Busch&Muller battery powered bicycle lights

Here's a guys full review of the new Ixon IQ vs the old one (the new one has similar output to the saferide, the older one was much dimmer) -
Product Review: B&M Ixon IQ Premium LED Headlight | Captain Overpacker

This is a gif he put together comparing the beam pattern of the old one vs the new one (note that the saferide is not in this, and that as always these pics usually appear brighter than they look in real life) -


Edit: The Ixon IQ is battery powered with AA's (they can be charged in the light though, which is pretty cool). The equivalent dynamo light is the Lumotec Cyo Premium, which has exactly the same output and is believed to use exactly the same led and lens.