While Mayco is not bringing SG-101 back, they have a glaze mixture solution that will create a fantastic chalkboard surface!
The two products you'll need are Mayco Underglazes and Foundations Matte glazes.
The ratio for the mixture is 3 parts Foundations to 1 part Underglaze.
For Black Chalkboard Glaze: mix 3 parts FN-304 Black Velvet with 1 part UG-50 Jet Black.
In a small cup, mix 2 parts FN-304 Black Velvet and 1 part UG-50 Jet Black to create the chalkboard glaze.
Note: The 2-to-1 ratio may also work; both have been tested. The 3-to-1 ratio seems to be less porous and chalk marks wash away with a damp sponge more easily at the 3-to-1 ratio.
A great container to use is a terra cotta flowerpot. They have always been an inexpensive way to plant seeds or repot flowers. They can be found at your local hardware and craft stores. They are plain with no character just waiting for a signature.