If you just search for the flights on Expedia or such sites then these fares often come up, but it's sometimes a matter of searching for each individual flight rather than just a round trip or multi-city.
What is better though, is a new tool since the last post:
Book with Matrix where you can just copy/paste results from Matrix (instructions are on the site) and it will try to find it for you.
(In your case though, if it's all Delta flights, they should show up just fine on delta.com. I'm seeing them for $785.81 per person there for those dates unless I'm missing something.)
I'm sorry. In writing and rewriting my post somewhere I lost the line indicating that that fare computation was for FIRST CLASS. And I have checked on Delta's website, Book with Matrix, Expedia, etc. None of them show that fare.
Does anyone have any suggestions for booking this fare computation?