In need of a vacuum system for router with a lot of Z travel

Hi
I have a router with 15" of Z-axis travel. I'm starting to mess
around with 3D work and I'm in the process of carving a piece that's
5" tall. I'm using a 6" long router bit. The vacuum attachment I was
using was designed for flat sheet. I need to come up with some sort
of rig that will clear the piece I'm carving yet will provide enough
enclosure so the vacuum will suck.
Any one have any brainstorms on this. I'm not looking for detailed
instructions just a nudge in the right direction. Unless of course
you have the time to give detailed instructions in which case I'm all
ears.
Thanks