I have noticed a peculiar behavior where if you have column widths larger than the total grid size, columns that do not have a fixed width won't render, even if they are supposed to. I have created a dojo that shows the problem:
http://dojo.telerik.com/@yazdog8/OSOKi/2
The "Contact Name" column isn't rendered on creation of the grid. If you were to hide a fixed width column, say "Contact Title", all of the columns that should be shown are present. However, if you re-activate the fixed width column you just hit, the column with no width is hidden again. I'd expect that even if all of the widths exceed the grid width, you would at least see something for the non fixed width column.