If you end up going with mosses, ferns, or most tropical plants, you may not need to worry about lighting.
A lot of typical houseplants are tropical understory inhabitants, and can live with very low light demands (why they make good houseplants). So whatever light you are using to work on your desk, and the ambient lighting may be enough.
You may not even need to hinge the glass top, if you have it inset, and have the front edge accessible, you could just lift it up, while the back edge is 'penned in' by the inset.
See if you can check out some sewing machine tables- a lot of them have mechanisms for raising/lowering/flipping the sewing machine out of the way when not in use. If nothing else, it could give you some idea how to structure the desk so that the terrarium part doesn't get in the way of using it as a desk.