My feeling is that stealth technology should be built into the ship, like it is on a real stealth aircraft or stealth ship. The invisibility generating "cloaking device" which could be moved from one ship to another in the ST:TOS episode "Enterprise Incident" doesn't make sense, but I could see some sort of electronic jamming equipment being so portable.
Whether Thom implements it or not, if you want to try a cloaking device ship in Artemis you could write a mission script. Just assign one of the player consoles a set of keyboard commands for controlling the cloaking device (at least an on/off switch), then build the enemy AI blocks so that they will ignore the player ship any time the cloaking device is on. You could even have the enemies talk to each other:
"What happened to the Earth ship? It was there just a second ago!"
"Damn the torpedoes! Four bells, Captain Drayton!"
(Likely actual words of Admiral David Farragut, USN, at the battle of Mobile Bay. Four bells was the signal for the engine room to make full steam ahead).