Here's a list of resources I collected regarding virtual texturing.
Clipmap.pdf (not virtual texturing specifically, but useful)
GIEGL-2007-QV1-Preprint.pdf (also not VT, but virtual shadow mapping)
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...)
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