I think the main problem is that there IS no deadline. How many parts do you have? If you've got enough, and it makes a good collab, do the following.
Make a deadline, say... the end of July. Then, you can send me the collab w/ all the parts working and flowing smoothly. I'll add the menu and credits (I'd prefer doing it, you may have trouble with my setup). I'll sent the .fla back to you, you can submit it, and we'll have a finished collab.
Sound like a good plan?