high performance client server solution in D?

[biocyberman via Digitalmars-d-learn]

I am considering to use D and its library to build a high 
performance client-server application. The client will be a cross 
platform (Windows, Mac, Linux) GUI program that can synchronize 
analysis results with the remote central server, and analyze data 
locally. It will also visualize big data files (about 10GB of 
binary data each). The term 'high performance' means it can serve 
several hundreds users with desktop application speed. Further 
more, heavy computation tasks will be done locally on the client 
side. This description is still vague, I know. But that's the 
best I can give for now.

I would choose 'dlangui' and check 'vibe.d' for a start. However, 
I do not need to access the central server via web browsers. Hope 
that you can give some thoughts about this design, what GUI 
library to use, and what back-end library to use.