I can't offer opinions on the rumble seat or the piggyback board as I don't have either, but I went out and took some pictures of the fold on my 08 Vista (the 09 holds 10lbs more but the fold is going to be the same as you can't fold the stroller with the rumble seat on).
The first
picture is just of the frame folded. The highest part of the frame is the wheels that come standard. I measured it at 10 3/4". With the handle in all the way the total length of the frame is around 30 1/2" and the width is 24.75".
The
second one is with the seat folded with it. The seat is facing forwards (it can also fold with it backwards but my camera died after this photo, the porportions are about the same only the highest point is 17" as it's the top of the seat). The highest point is the canopy on the seat at around 14". With the foot rest extended out all the way the length is around 40" and the width is the same as above, 24.75".
It can also be folded with the seat in reverse but my camera died after those two pictures and DS is up from his nap. I did measue the height however and it was at 17" with the seat back being the tallest point.
Overall I really like the Vista as a full sized stroller but probably won't keep it past when DS is two. We don't intend to TTC the next one till he's four (DH is going back to school) and will probably sell it and get a Mac instead as the toddler seat isn't very tall and then buy a new cool whatever is out in four years. If you have any other questions about the stroller itself or need different pics let me know and I'll see what I can do.