First of all, yes, Valve is making VOGL run on Windows. John McDonald, who formerly worked at NVIDIA as an OpenGL guy and then joined Valve to work on VOGL, has been tasked with porting the OpenGL debugger. The code is still very fresh with the VOGL core library and VOGL code generator just running on Windows as of this morning.
Meanwhile, Mike Sartain at Valve has been working on a new tracing/replaying/trimming regression and smoke test system. Carl Worth from Intel meanwhile has broken up the VOGL source repository into vogl_src and vogl_chroot repositories.
Rich Geldreich in his blog post also mentioned they have been testing traces from some new game titles that will be released later this year on Steam for Linux.