ZZP did it from the top, motor an trans still in the car an they took a picture of it. But they were using every inch possible an I believe they actually shifted the motor to the left an the trans to the right to get the space. Meaning it might be more of a PITA to do it that way, but to answer the question yea it can be done an has been.
EDIT: Found the thread. I think the pics are gone but he describes what they did a little ways down.
http://www.clubgp.com/newforum/tm.asp?m=1517071