I don't know if they're beer-battered, though I'd be a little surprised if they weren't; but Jacob Wirth's has a pretty good fried pickle with some good sauce on the side. I'd say it was the best thing on their menu. ;-)
The Local in W. Newton and the Fat Cat in Quincy both do good versions. I'm a little puzzled to see some places battering and frying whole spears. The Southern-inspired version I expect to see uses pickle chips.
In Cambridge, Cambridge Common, on Mass Ave between Harvard and Porter, does excellent fried pickle spears in a lightly spicy beer batter. The ones at Redbones are good too; the batter is much lighter there, and they use chips instead of spears (in addition to jalapeño slices).