Bicycle Mechanics - 10-speed chainrings less durable than 8-speed?

Now, I know that a 10-speed chain will fit on chainrings originally designed for an 8-speed system, etc. And I suspect this means that the actual chainring teeth are no narrower with cranks designed for a 10-speed system, and so there's no reason the chainring teeth should be less durable than chainrings originally designed for 8-speed drivetrains. Can anyone confirm on this?
The reason I'm asking is that I like to run a singe chainring on my commuting bike (http://www.unc.edu/~cupery/pics/2005/10-commute_bike) and may be building up a fixed-gear soon as well, and I want to know if there's any downside to picking up a chainring designed for a 10-speed system. Thanks.

For a fixed gear or single chainring crank, you will do better with the older design "flat" chainrings. Newer chainrings have pins and shaped teeth intended to enhance shifting speed. That's the last thing you want with a single chainring.

For a fixed gear or single chainring crank, you will do better with the older design "flat" chainrings. Newer chainrings have pins and shaped teeth intended to enhance shifting speed. That's the last thing you want with a single chainring.
True of most newer chainrings, but not really true of the small chainrings from double cranks - those 42-tooth guys that don't need help to be shifted into, because there's no chainring smaller than them. These will sometimes have symmetrical teeth, even in 10-speed versions.

And my question remains: are the teeth on 10-speed chainrings narrower (and therefore less durable, all other things being equal) than 8-speed chainrings?

Not really, it's just the chains that suffer more because of their width. Sprockets and chainrings should have equal durability regardless of the number of cogs there are. The only real difference is the spacing between them and that won't affect durability I shouldn't think.