Thanks for all the replies.
Yep, you're right: it just looks wrong. And I've wondered if it would be more tempting for kids, etc to climb on when the van is in a parking lot than a standard rear ladder would be.
The security argument for a kayak is good. Ditto skis.
As for not wanting to carry more in the van -- it has dawned on me that of course I'll removing stuff -- rollatable, sunshade, backpacks, tent and putting it in the roofbox, so there would in fact be room for a telecoping ladder.
These roofs are easy to dent -- like 86Scotty, I didn't see the dent on the roof of my van until after purchase, when I climbed up to look at rust in the gutters. Looks like the previous owner (or two or three -- I'm number 4) got whacked by a branch.
BTW -- if anyone is looking for Yakima raingutter towers, check eBay. I got a set of four in great condition with locks for $50. I used my twice-yearly REI 20% off coupon for the 78" bars.
Now I need an awning to attach to the Yakima bars, perhaps as LenS has done.
Cheers,
GreyDawg