Looks like there's an Eagle Rider in Manchester. Probably at MOM's I would guess.
I've never rented from them, but I did consider it when I was in Las Vegas a couple weeks ago. The Vegas one had all sorts of bikes, from Harley Road-sofas to BMW's and Hondas ST's. Was fairly reasonable, price-wise, but the deposit was pretty high. They have a link on their website for group rentals. Worth a look-see.
Additionally, it looks like they've got a Boston location, and a Foxboro one which would definitely be at MOM's South.
Chris in Norwood