We are losing the E-450. However, we are gaining the T-450, and the Ducato.
The Fiat Ducato has been used in Europe and around the world for years, and actually is a chassis that is built for motorhomes (fiatcamper.com), and even though it doesn't have the oomph of the Ford V-10, it is a solid platform, and will provide decent fuel economy. We are finally getting this, rebadged by Dodge, but it is a good platform with high MPG ratings, and very upfitter friendly.
Of course, there was a gas pusher that was announced by one of the chassis makers, but I forgot whom it is. Apparently, they are going Ford's route of using common rail EFI and turbos to make a gasser. Not a new technology, but something not seen since the days of King's Highway class As.