I've not seen any unichips in place, but would it be possible to make a sort of sandwhich connector for pluging it into the ecu loom? So that it could be removed very easily.
Ie, get another male and female ECU connector and link all the pins and tap off only the ones needed for the unichip. Sourcing the connector blocks would be the hardest part.
The one to connect to the ecu would be easy from a scrappy, but the one to connect to the car loom may be hard to get.