Tom Keffer suggested I look at the Solar Stik:

http://www.solarstik.com/marine.php

This is built strong. I contacted Jeff Inshaw, their marine rep and, not surprisingly, the cost is higher than I wanted... somewhere in the $2k-2.5k range. This company's main business is supplying portable land use units for the military. Milspecs... tough and expensive.

Then I found at our fine host Phil's chandlery:

http://shop.sailboatowners.com/detail.htm?group=1714

Dave at their office was very helpful, and in light of my wishes to customize, referred me on to the manufacturer in Michigan:

http://www.custommarineproducts.com/solar-panel-mounting-systems.html

I reached owner Tom Tinnerman who said he'd be happy to come up with something that would work for me. I expressed some misgivings about the ability of the unit to stand up to offshore conditions. He said that his units have been tested repeatedly in Great Lakes gales. He also said that he has sold quite a few to NASA. They did a 100mph wind test on them before placing a larger order.

Tinnerman in turn referred me to

http://www.foster-wills.com/contact.html

I got together with Ed Foster at their office in Seattle to see a unit in the flesh. Their emphasis is importing and wholesale of alternative energy products, but will also deal with end users for support.
See the photo with this post and the web link to a few more photos.
http://gratitude.mine.nu/Grat/SiteAgogo/Photos/solarmount/index.html

The mounting pole is 1.5" diameter stainless. By chance, the interior diameter of my existing Novalift (outboard lift) base is just about the same diameter, slightly larger. I'm hoping that it will actually accept a 1.5" pipe. That would yield a removable system that would be quite strong. On the downside, it will be low enough to be a head-cracker. I also have worries about proximity to the backstay HF antenna. (There's always something to worry about!). I may give it a try for some inshore cruising and make a decision later regarding offshore.

The 120 watt monocrystalline panel is a no-name brand being offered at $5/watt. At least I know where to find the importer if I have a problem.

I'm a bit uneasy about the mechanical stability of these units in a blow. While they may be removable, 3am with 50 knots of wind and building seas would not be a great time to remove the unit. At least tilt angle and rotation could help reduce windage without dismounting. I wouldn't relish steering the boat with it.

I'm thinking about getting three of the Ganz 30 watt units (similar to DH Larry's) to lash down in various locations as needed. 120+90 watts? A good start.