They are all 26 inches, T-shaped
The brand of the piano used by Jake Shimbukuro is KAMAKA. There is no model number, it is a custom-made one by Jake. However, many of them were specially made and sold as "Jake Shimbukuro's signature piano". Except for the different headstock, everything else is the same
He is in the video I have used three KAMAKA pianos in total, all of which are T-shaped. The string brand is D'Addario, and the classic model (HI) GCEA, which is all nylon (this brand also has a model with a metal third string).