Technologies advices - Vector graphic [on hold]

I have the need to draw vector graphics starting from a DWG file. Following are my requirements:

1. Environment: Windows


2. Graphics: Vector graphics


3. Input file: DWG format (third party software for a possible conversion in other formats can be considered)


4. Magnitude: The number of shapes can exceed 100000 units (performance is vital, the application must be always fluid)

The current main application uses the C++/MFC environment with EMF files (converted from the originals DWGs). An update to the application is required.

Which are the current technologies better suited for this kind of task?

At the moment the solution would be to use the .NET environment by means of WPF, for the rendering part, and the SVG format:

pro: a large part of the main application uses .NET (programmers already know c#/VB.NET languages as well as the WPF framework); SVG is an open standard.

cons: WPF is slow (even by using Visual objects); SVG is text-based (huge files).