I was very happy when we got to start writing completely on paper though. I hated the thing, I remember, since I loved the crisp lines one gets from pen and pencil on paper.

See, I was a little art snob even back then :)

In India, Sureshchandra & Brothers appear to still make slate pencils. They state:

Use of Slate and Slate Pencils in lieu of Note Books and Lead Pencils is comparatively economical and environment friendly.

They even sell a slate holder!

Using it as a “telephone message taking device” (as you put it) is very clever ;-)

In Germany there are at least two manufacturers that offer slate pencils, namely Faber-Castell (“Heft & Tafel”, also available in a Jumbo Grip version) and Rheita (“Milchgriffel”). – I was suprised to see that also slates in many different sizes and designs are still available. Among them are small ones with a wooden holder that can be used as place cards and very large ones for restaurants. There is also one variant with a decorative coil at the smaller edge which makes the slate look like a paper notepad.

Only a few months ago I have seen a slate in use – an older man from a boat hire kept track of the time on it, and in view of the condition of that slate and the matching pencil he has never used something different. The signs of usage made it even more appealing to me!