Here's a list of resources I collected regarding virtual texturing.

PDFs
05-JP_id_Tech_5_Challenges.pdf
AcceleratingVirtualTexturingUsingCUDA-b10648-49.pdf
Clipmap.pdf (not virtual texturing specifically, but useful)
GIEGL-2007-QV1-Preprint.pdf (also not VT, but virtual shadow mapping)
LTU-HIP-EX-10009-SE.pdf
unified-texture-management-for-arbitrary-meshes-RR-5210.pdf
VirtualTextureReadme.pdf
VirtualTexturing-AC07808876.pdf

Other
johnc.plan.htm (not virtual texturing, but John Carmack describes why virtual memory should be on GPUs, such as the new AMD Radeon HD 7000 series... 11 years later...)

Mine
I have a few plans and ideas written on paper, plus stuff barely related to virtual texturing already done. I'll have to formalize and convert the stuff I've written on paper before uploading them. Links will appear here periodically.
Efficient Tile-mapping on DirectX 8 Level Hardware
Efficient Tile-mapping Revisited