gbin -
Handling the leaves and needles _before_ they enter the pond will be the least labor intensive and the most economical and feasible. There are always trade offs, and here is no exception. Do you really want to skim a 2 acre pond on a daily basis for 1-2 months? Do you want to dredge up the fallen needles and leaves each year, which by them may include valuable life such as damsel/dragon fly larvae, crawfish, etc.?
I understand the aesthetic concern, but a fence would be for 1-2 months, a fence is proactive, and a fence would allow you to spend your "free time" doing other things.
Other options? Chop the trees ... Stand beneath them and use a blower to blow the leaves off prematurely and keep them from the pond ... take a professional landscape portrait of the pond area and have it printed and scaled so that the misses _thinks_ she's look out upon the pond but in fact is looking at a printed scene ...
