Want a super wide 29er rim? This may be your best bet. At 40mm internally, this carbon rim is the widest we've seen yet designed for use with a standard MTB tire (non plus size). The spoke bed is offset by 5mm to help build a stronger wheel. It weighs 450g and goes for $699 a pop.
The photos above show the difference in the width of a 2.3-inch Maxxis tire mounted to the Kappius rim and a competitor's rim with a 21mm internal width. In a side-by-side test with the same air pressure, the sidewall support offered by the tire on the wider Kappius rim was far greater.
2015 Sea Otter Classic Pit Bits