Einstein famously came up with E=mc2 in the early part of the 20th century and some 40 years later the engineers came up with an actual demonstration of the equation.
What is needed at this point is a careful description of the phenomenon included in the math so we can get to the real business of building demonstrations on lab benches.
Some aspiring SF writer could certainly have some fun writing a description of the first such experiment on a bench somewhere and the result of moving even a small object at relativistic speeds across a laboratory of necessarily limited dimensions.
In the meantime I encourage the boffins to keep crunching the numbers. I'll keep a space clear on my workbench.
Scientists investigate that which already is; engineers create that which has never been.A. Einstein