I don't have any benchmarks, but I do customize ADT using Lisp, VBA, VB6, C++, and vb.net.
That graph is very misleading, vb6 compiled as an early bound dll will run much faster than VBA. The graph is showing VB6 as late bound which is dumb usage of vb.
Dotnet is faster than VB early bound, but slower than objectARX due to marshaling of the parameters and return values.
I actually started a benchmark program, but I did the vb.net version first and it ran so fast I was satisfied. The only thing I have seen in dotnet that runs slow is the jig code. I would stick to C++ for those interactive loops that have to draw a lot.
Chris Arps