Just a couple more links and ideas.
Also try going to http://www.motherearthnews.com/index.php?
page=archindex and typing "maple" or "syrup" or "sugar" into the
search box at top right (not on the left - that's the book search).
I thought I read about a solar evaporator someone used to make
molasses, but can't seem to find it. What about using the parabolic
solar mechanism (usually used to make a solar stove) to concentrate
heat and boil the syrup? With molasses-making, they use several
metal trays in a line, evaporating the water out more in each tray,
and sometimes maple syrup is made the same way. One could use a
parabolic setup to heat each tray and perhaps speed the operation.
There are many places on the internet to get clear instructions on
making these parabolic setups at home, using cheap and available
materials. I like http://solarcooking.org/
- under "Plans", click
on "Parabolic Cookers".