I have the eurocampers.com one, but I don't see it on his website now, but
he may still have them.  I use it for fresh water.  One issue as a grey
water tank is the large drain is molded up into the tank so about 2 inches
of water in there wouldn't come out unless you add a small drain plug at one
end.

But a better idea is buy a couple 4 or 6" PVC pipes, cut them to the right
length, somehow connect them together, glue on some standard plumbing caps
and one drain, and mount them under the van in the frame rail.  They would
be more sturdy than the plastic tank and would tuck out the way a little
better.

>From: BA <oddstray@ODDSTRAY.COM>
>Reply-To: BA <oddstray@ODDSTRAY.COM>
>To: vanagon@GERRY.VANAGON.COM
>Subject: Installed gray water tank
>Date: Wed, 20 Sep 2006 21:37:06 -0700
>
>Hi, all,
>
>We're getting around to realizing that we'd like an installed
>gray-water tank.  Up till now we've used the "bucket under the van"
>solution.  But we'd like to be able to get more adventurous than just
>the developed campgrounds, and an installed gray-water tank seems like
>a sensible idea.  (We have a porta-potty for black-water purposes.)
>
>We've searched the vanagon archives and the web with no luck.  We had
>searched several months ago and managed to find information about
>installing a tank ... but where did all that information disappear to
>now that we need it?!?
>
>Anyway, if someone could point me to some information we'd be grateful
>... thank!
>
>
>B&S
>'87 Westy 'Esmerelda Blanc'
>SoCal