The largest thing I hauled was a plastic shed like this twice when I moved. Didn't want to take it apart. Can't find the picture but it was large and awkward.
The heaviest load I have ever hauled was 3 of these at once. Kind of stupid, but a short distance and a testment to airbags.
TXI - 1,000 lb. Pea Gravel - The reusable gravel can be transported from site to site. It keeps your job site clean without needing barriers. - THD SKU# 874917www.homedepot.com