It's a really good project in many ways, but until recently, I thought I was the only one making a T-beam bass.
To my delight, as I discovered here, I am not the only one. Kaspar Torn is building one as well. It's still in its early stages, and so far, it looks very promising. As you can see from the pictures, it differs from my own project in a number of ways:
Strings are anchored in a bolt through the vertical flange
Tuners upside down
This project is going to be interesting to follow. Kaspar leaves many options open, such as a detachable acoustic body and a spike, allowing it to be played upright.
I will post updates as the project moves along.