Miniature Arduino board with 2x USB Type-A connectors + 1x USB for programming?

USB conversion board assuming you understand USB protocols and coding.

The device is the equivalent of a Leonardo (32u4) and USB host shield but on a board the size of a USB thumb drive. The software is designed for USB keyboard remapping (for example, Dvorak) and hardware macros. But it could be reprogrammed to do other USB protocol conversion assuming you have the coding skills.