There are a few bloggers running GURPS fantasy games out there.
I am running my own, of course, and it's heavily AD&D/Rolemaster influenced. I'm going with pretty strict templates, the more gritty rules, and an emphasis on scarcity of goods and slow growth of personal power. I'm also running a megadungeon.
But I'm not alone.
Here are the ones I know of, in no particular order. Characterizations and descriptions are mine, and so are any errors in them.
Mark Langsdorf is running Savage Tides with GURPS. They're using cinematic rules like Wildcard skills (i.e. replacing the knight's various skills with Knight! - a one-skill solution).
Patrick Halter is running Temple of Elemental Evil with GURPS, in a very standard DF-style way but with lower point characters than I do. PCs are (for now) raiding the moathouse, but the temple looms on the horizon as a campaign tent-post megadungeon.
Ken Harrison is playing in Robert Conley's Majestic Wilderlands in a GURPS game. Here's a sample session report.
Christian Blouin is running a GURPS game set in Middle-Earth.
Grouchy Chris is running a GURPS game where the PCs are in a traveling circus - here's a session summary.
Douglas Cole is playing in DF Jade Regeant, and occasionally posts summaries.
Am I missing any GURPS blogs with session summaries? If so, let me know and I'll go and read them.
Editing Later: A couple new places to look:
Michael Keenan's DF Game
Trees and Caves
Editing 3/21: One more.
Jason Wollard's DF game
Editing 3/23: Still another.
Neon_goggles's GURPS Fantasy Game