I've just received one of the few precious XO 1.5 samples, since I'm supposed to be working with Chris Ball and others at OLPC to help them with getting the VIA hardware fully supported, e.g. integrating/testing support for the specific panel, etc.
It seems to be booting fine the current xo-1.5 branch of the OLPC git tree, and the basic operation of all major peripherals is fine. Stuff like power management and support for DCON are still requiring some work, of course.
Today I'm still busy with generic non-OLPC VIA driver related work, but tomorrow I can hopefully look into OLPC related issues.