Hi yourself, I've mostly just been reading the mail and resisting (most)
temptation.

Thanks for the links, I have that reservation about messing with the
structure which is why the Sprinter is an outside possibility. The company
that would modify the Sienna has a long and good reputation in doing these
conversions, but am still cool to the idea of that much structural change.

 Well, at least you know better than to consider a Caravan...  ;-)

 The Sprinter would probably last you because it's a commercial
chassis, but consider the roof height - you can forget about getting
into most underground parking and parking structures.

 Even the parking structures where there's one excess height floor
you'll fit in, before the upper floors start with reduced clearance -
that's the parking spaces closest to the door, and all the lazy
a.sholes in the Mercedes and Porsche and BMW sedans fill those spaces.

 I'm tempted to put up signs at the one parking structure like that
I've tried to use:

"All passenger cars belong on the upper floors, these spaces are
specifically reserved for oversized vehicle parking ONLY.
 If your SUV, Truck or Van is NOT at least 6' 6" tall, or any
passenger car is found parked here before the entire structure
upstairs is full to capacity, it will be towed and may be CRUSHED INTO
A COFFEE TABLE SIZED CUBE at the owner's expense."

 And to seal the deal, put one of those "compact(ed) car" cubes into
that dead space in the corner as pop art.  The sign over that corner
reads: "And this guy didn't believe we were serious..."

 That's more a problem of the reliability of the base vehicle.
Unless the floorboards split and dump you on the freeway, of course.
That's the problem with making custom mods to a vehicle, you are kind
of stuck with it for the long haul, till it's flat worn out.  You keep
spending to fix it when it breaks, rather than sell/junk it at a huge
loss, and spend a lot to buy and modify another new car.  

 An old Toyota "Two Slice Toaster" Van would be perfect choice for
"can't kill it except by a direct hit with a Howitzer" reliability,
except for that stupid mid-engine hump in the way...  ;-P

 Take the "new car" for a test drive over to a trusted body shop, and
let them inspect the work quality of the body modifications just like
you would take a used car to a mechanic for a once-over.  A trained
eye should be able to spot really bad design or really sloppy work
that will fall apart - you can only hide so much with Bondo.

 --<< Bruce >>--