Thanks for the response!
"1) don't force that behaviour on visitors....they hate it!"
Oh, trust me, I know that. I hate it too, but the client is dead set on it.
"3) wait for CSS3 which allows target behaviour"
HA! The client's big on IE6 support. That ain't gonna happen.
"4) switch to transitional"
This was a last minute requirement, and the site's basically done. I would be wary of switching doctypes at this point.
"google xhtml strict target blank to see if you have more options I guess....."
Yeah, I'm going to keep Googling.