I didn't realize that LVM could handle this scenario. Thanks for pointing that out.
To be honest, I never like to make changes to the partition table of a disk without rebooting or hotplugging the disk. The kernel sometimes doesn't refresh its view of the partition table (or has this been fixed in newer kernels?). So while online resize of physical (windows) partitions without rebooting may be possible in theory, I'm not sure if I would choose that route for an internal disk.