As a DL diamond, the OP would enjoy many of the status benefits of Velocity Elites when flying DJ / VA.

It's a walk up for that. FWIW, on a reciprocal basis, when Velocity Platinum, I have been treated as a DL Diamond when travelling in the USA (better even as I get DL lounge access on domestic USA itineraries).

Qantas will status match in rare situations - in this case they may consider it rather than lose out to DJ if the OP can show significant upcoming travel.

There is a recent anecdote of a NZ *E being matched to SG. (http://www.flyertalk.com/forum/air-n...-matching.html)