While browsing at our local outdoors = shop, I discovered something far less expensive that might be a usable solution = for secure luggage rack storage.
 
A company called Contico, St. Louis, www.contico.com manufactures = polypropylene (sp?) boxes for all sorts of purposes.  At the outdoor shop, I = discovered a 32"l x 17"w x 12.25"h footlocker which just might do the trick for = me.  I plan to go back tonight and purchase one to check it out.   = Since 32" doesn't fill out the luggage rack, I'll have space for a gas can since I = haven't found any alternative way to carry one safely.  I could also store = my folding chairs alongside the footlocker.  It has little wheels on = one end so that, when it's on the ground, it would be easy to move around.  = It is extremely light weight - I could pick it up with one finger on each = hand.  It sells for $30!  And this is not any kind of a discount = store. 
 
What I will do if this seems like a = good thing is this:  remove the luggage rack, drill appropriately spaced holes in = the bottom of the luggage rack, to be mated with holes in the bottom of the footlocker.  I'll glue bolts upwards through the holes (with some = kind of metal reinforcing under the fiberglass)  to go into the holes in = the footlocker, fasten the footlocker down with rubber washers and butterfly = nuts on the inside of the box.  The footlocker has a place on it for a padlock.  If you space it really well, you could have the = footlocker face either the front or the back.  Since we will be crossing a = great number of borders in South America, it occurred to me that I didn't want = to have to pop the top at the border so that the border guards could search the luggage.
 
For anyone who wants a larger storage = space, I saw a truck storage box on the website that is 48" long.  I'm not sure = if that would fit in the luggage rack or not, but it's close.  If anybody = finds these footlockers on the web, please let us all know.  Heck, a = discount off of $30 would still be a good thing.
 
I'll let you know how it works = out.  If it's not good, I'll go back to the fiberglass lid idea.
 
Jeanne
'87 Syncro Westy