Syncros did indeed make one and I have a pair but I've just moved and I can't find them. If I find the Sidi shoe box, I've found the steerhorns.
I've only seen one pair of them for sale in the last few years. They're nice but not nearly as nice as the conventional steerhorns. The quilled 'horns are nicer than most other bar ends, but they are not smooth on the outside but have a hole bored where the quill bolt goes. The next generation had a totally smooth ball and clamped from the back, much nicer. If I can dig them up, I'll post a picture.
'guin