I have come across an issue where we cannot calculate shipping on an item over 150lbs.
I first have tried the solution outlined here http://www.magentocommerce.com/boards/viewthread/179546/#t234403
(set max. package weight -150lbs and Packages request type - divide to equal weights)
Now this works for an entire cart of multiple items. For example if you have a cart with 2 items and a total weight of 160lbs, it will split the cart into separate boxes and give a rate. However if you have one item in a cart at 160lbs it will simply not calculate. Does anyone know how to make it split a single item that is over 150lbs and give a rate?