Ignacio's stuff is based on the Charles Loop paper "Approximating Catmull-Clark Subdivision Surfaces with Bicubic Patches". It's funny that it's really just a fancy version of the PN Triangles hack; the actual geometry surface made is not continuous, but there's a separate tangent field over it which makes the shading look smooth.
While there I noticed a bunch of Loop papers I hadn't read. The Loop-Blinn thing from 05 was particularly interesting because I've talked to a few people in the last N years about rendering fonts better. Thatcher worked on it a bit at Oddworld, and recently Sean's been doing it at RAD for our new GUI product. The Loop Blinn Paper described how to use a pixel shader to shade quadratic or cubic curves. The cubic stuff seems like rather a pain in the butt, but piecewise quadratic is certainly good enough for glyphs. Also they sort of gloss over the details of anti-aliasing, which is of course crucial; there's not much point in being this careful with curves unless you're going to get the antialiasing right.
Zheng Qin, Michael McCool and Craig Kaplan seem to be doing a lot of work on this stuff at Waterloo. I sort of assume you're familiar with the simple Valve Alpha-test Distance Field thing ; the Qin work is the basis of the Valve technique and is more robust and general, but much more complicated. The Valve technique is probably okay in a game development scenarios where artists are monitoring how their work looks in game and are used to tweaking with weird algorithms, but it definitely has parameters that you have to tweak, and the use of single (or even two) distances can cause bad degeneracies if you're not careful, whenever you have details that are close to the size of a pixel in the distance map.