It's possible........ but not the greatest idea on the plant for several reasons that have been discussed here over and over.
It's not difficult or expensive to find a computer that could actually fit into the cab. There are a lot of sources of used and unwanted hardware out there. People are always upgrading their machines and dumping hardware.
Try your local rubbish tip / refuse disposal point.... in the UK and the USA they tend to haul out anything that they think they can sell off. Usually it goes for the price of a couple of pints of beer.
So far I've had three working computers from my local tip... including a complete Mac system with monitor printer and software that cost me £8. All of the ones I've acquired were perfectly capable of running Mame and 90% of the classics. Go digging!! You never know what you might find.
Try local junk shops, charity shops, local free adds papers, adverts in supermarkets.. etc etc etc.... You will find something that will work well in your cab, and probably for less than the cost of that cable and KVM Switch.
I'm building a bartop at the moment that uses parts from a computer that cost me £3 at the tip.
Best Regards,
Julian (Fozzy The Bear)