The Buzz Pro and I'm pretty sure the Provari also are shorter but not by much, The BP is 1/2" shorter, hardly any difference.
The Lavatube is just being released and I don't know the exact measurements but it should be close if not the same length as the rest of them.
Basically in a VV tube your looking at minor differences in length between them. I did read from a vendor in the Power VV thread that the LavaTube will also be available in a tube that uses 1 18350 and that should really cut down on the length but that's probably well in the future as they are just now rolling out the 18650 version. Also Notcigs is working on a shorter VV mod, I think it's latest name is the Envy and if they can get everything worked out should be available sometime after Christmas.
So right now, you might get a little shorter but not worth trading for imo but 2012 looks good for some shorter VV tube releases if you can wait.