If your 30% off coupon is still good, you might take a look at the Belelli rabbit front seat. It is good up to 35lbs and a front seat would allow you to take both kids and have your panniers. It's a relatively small investment and once you develop some biking habits--see where you are going, how often, etc. you could reevalaute the Weehoo option. At 2.5 my son sat happily in his front seat for 30 mile rides on back to back days, content to chat with me as we rolled along. I agree that trailers are boring and create drag, but "static" seats are plenty fun if you engage the child.