The most recent melon beer I think I've had was a watermelon at 21st Ammendment in San Francisco, where they actually placed a small watermelon piece on the rim of the glass. It was decent for a few sips before losing much of the melon flavor. Enjoyable but more novelty than great beer.
Hopefully Pub Dog's efforts prove worthy.
UPDATE: From Alexander D. Mitchell III, Beer In Baltimore blog maven and writer for Mid-Atlantic Brewing News
Yeah, but you'll have to read Mid-Atlantic Brewing News to figure out who's doing the OTHER melon beer this summer!