Levels are a very practical addition and are not so unusual on cameras from the early 20th century.
Unless there is an option like a bag bellows, interchangeable bellows wouldn't be worth the extra cost. The bellows should last 10-15 years or more, and will probably have to be fabricated from scratch anyway, so a bellows with a frame at each end, screwed to the front and rear standards in the traditional way will be easy enough to deal with for such an infrequent repair.
It's hard to say what a traditional field camera can add to the existing market in terms of features. The likely attractions might be low cost at the entry level of the market or high craft at the opposite end.