Garmin did indeed buy Vesper, but it doesn't seem to have been entirely a catch and kill operation. Vesper's most recent products, the Cortex line of AIS, is on the Garmin website:
They're just called Cortex, no mention of Vesper, but it's the same Vesper Cortex system that I've been lusting after for several years (but not buying because, well, daddy needs a new sail first).