Hello, I have pretty much the same problem and am at the point that I don't know what to do short of eliminating the tunnel or fabricating something myself.  I would think this is a problem that many on the list have and that some smart entrepeneur has figured out a fix and is willing to sell/share it.
Cheers
Jaime

--- On Sat, 2/13/10, C. Chris Snyder <ccsvanagon@WMCONNECT.COM> wrote:

> From: C. Chris Snyder <ccsvanagon@WMCONNECT.COM>
> Subject: A/C tunnel
> To: vanagon@GERRY.VANAGON.COM
> Date: Saturday, February 13, 2010, 12:28 AM
>
>
>  Howdy group:
>
> I know that he long, tunnel that is mounted on the ceiling
> and goes from the evaporator to the front of the van is no
> long er availble so, does anyone have a god one they would
> be will to sell? also, the evaporator housing as well. Mine
> has cracked (the tabs that hold the sections in place) and
> so I have super glued the ones that keep falling down in
> cold weather.
>
> I need it for my 1987 wolfburg edition
>
> Thanks in advance,
>
> chris
>