The only solution I've found is to grow mostly cherry tomato varieties. This way, despite the squirrels swiping as many tomatoes as they like, I still get a sizeable harvest.

I realize this may not be useful to you this year - though, if you plant Sun Gold or Sweet 100, my guess is that they'll give you a harvest this year. Probably won't magically save your current tomatoes, however.

In years past, the local squirrels would pick my full sized tomatoes when green, carry them to the base of a tree, try to climb up the tree, realize the tomato was too heavy for their neck, try to climb up the tree BACKWARD, then ultimately give up, leaving the tomato at the base of the tree, as they scampered back to swipe ANOTHER TOMATO and repeat, resulting in small piles of green tomatoes at the base of their favorite trees.

Lisa

*snicker*
Forgive me, but both stories gave me a giggle. :P
I hope the mischievious squirrels leave you some tomatoes to enjoy. :)