Technically, he's only the third-tallest halfling in history, but then again, we have no evidence that Belkar benefited from the effects of an Entdraught.
On a less Tolkienesque note (alas), I got around to checking the SRD, and JumboWheat's memory is basically correct. The tallest a male halfling can be is 3'4" (2'8" + 2d4 inches; women are 2" shorter). So I guess that (probably) settles it.