I have a toilet drain leaking and it is not easily accessible, without cutting a hole in my ceiling. Is there a way to insert a new pipe within the old past the leaking point?

If I understand correctly, you don't want to cut open any walls or do any medium to large project on this. And you would like to INSERT a pipe into your existing pipe as.. almost a leak-guard. I would strongly suggest you do not do this. If you don't wish to open the below ceiling, I would suggest you TURN OFF THE WATER then remove the toilet from the floor, cut open the floor and replace the pipe or properly seal it. Adding a new pipe will one, be impossible because you will not find a pipe that is smaller then the one you are using and yet large enough to not permit any water going between.

And secondly, adding an inner pipe in a TOILET pipe will likely cause horrible problems with, shall we say, "blockage". The inner pipe will catch "material" and could very well make your problem much worse. If you have the money, I would hire a plumber, if not I would research how to do it properly.

ON A SECOND NOTE: If in this bathroom you happen to have a shower or possibly a sink which water often overflows in, you may just have a problem with overflow. I recently had a new shower installed and the corners where the wall conects to the floor had to caulking around the tile. Even the connection of Bathtub to floor and Bathtub to wall did, stepping out of the shower the water dripping from my feet would seep through the crack and cause several large wet spots on the floor below.