Hi,
It comes with an extension cable, but I understand the need for simplicity. I've been toying around with the idea of doing a redesign just for PCE. However, it would probably only be 30% or so smaller.
The reason it is large is because it uses actual 1980s hardware - no microcontrollers are used. If you use a microcontroller, you introduce lag (and possible bugs, and are lifting the code from someone else likely), which is already being caused by the wireless conversion. Currently, I only make lag-free controller adapters.
-SSF