Options for longer 4mm bits?

I love the driver kit from iFixit, but sometimes screws are recessed too far and unreachable given the diameter of the drivers, even with the flexible extension. Are there longer bits available with the 4mm hex shank?

Other options seem to be purchase multiple thin screwdrivers with long shanks for each type of screw, or to use a 1/4" adapter and purchase a set of long-shank bits which are normally used in power tools.

A set of bits I can easily store on my small workbench is preferable to adding more screwdrivers to dig through my toolbox. Thanks for your suggestions!