The answer to your question is yes. Would I do it? No.
for all of the reasons listed above. It will be tight and the risk of some type of minor damage would be to great for me.

 

I tried to get an ultra and my street glide in my 6x12. I could have done it with stock bikes and at least the bags facing each other off. My buddies bike had highway pegs and I believe bars that would just not allow it. I think a minimum comfort zone would be a 7x12.

 

Rounders will be along soon to give us the official word as soon as he gets out of his meeting with NASA till then we will have to wait!!!
I have hauled my Ultra and my softail standard in a 6x12 at the same time but I think two baggers would be pretty tight.
plenty of room for just about any other combination such as my two softails

would want to use two good quality chocks if you gave it a try but im afraid it would be really tight!!