I really appreciate you taking the time to post this. I have already built my table, though. Like you, I was uncomfortable with the glue. I made some brackets out of quarter inch clear acrylic:
The brackets work well, and I think look nice. Unfortunately, the Capita legs are the weak link in this design. They are fine to support the weight of the GF, but if you try and lift up on any shelf except the bottom one, they will separate like this:
The threaded rod is a good idea, and one I will give serious consideration if I ever rebuild the table. BTW, here is a pic of how the table turned out (pic is pre-reinforcement of top shelf - see below)
I collaborated with another user here, who provided many good suggestions for the design. He is planning on posting a full write-up on this, so I’ll save the details for that. But I do want to say, if you use the alternate top shelf that @chris1 suggested, you should seriously consider reinforcing it, as it is a very thin layer of wood over a very sparse frame. I built a supplementary frame to reinforce it - pic below.
EDIT: Attached zip file has the Illustrator source, PDF, and SVG for the brackets and the drill template, as well as an image scan of the metal bracket that’s on the top of the Ikea Capita legs.
Ikea Brackets.zip (4.0 MB)