We've released the Shadowcaster on the Dungeon Master's Guild.
Inspired by the original Tome of Magic class for D&D, this 5e version is written by the original Shadowcaster author, Ari Marmell, and was developed by Dan Dillon, who has gone on to be hired by WotC.
I'm considering it. Obviously, unlike the Shadowcster, I won't be able to make the "by the original author" claim. But I liked the Binder, and I have some thoughts as to how to make it work in 5E.
The decision of whether to do so or not is going to be based entirely on how well the Shadowcaster sells. If this one does well, I'll absolutely do another, but if it doesn't, I just can't afford to devote the time and energy to it.