ChunkedLOD
Info
This is ChunkedLOD implementation in C# and XNA based on
http://tulrich.com/geekstuff/chunklod.html.
The architecture isn't good for XNA but you can always change it, maybe sometime I'll change it myself. If you don't like that chunks are drawn when the texture isn't loaded you can change it in ChunkLod.cs
Download:
ChunkedLOD ProductionOlder implementation for Managed DirectX can be found
here
Screenshots

Not using texture blending

Using texture blending

Wireframe mode