We use 54 inch for the $75 and $100 sprays, the 60 inch for $125 and up, and we have the white, wooden John Henry ones - I believe they are also 60 in. - for $150 and up if the customer prefers them.
As Cathy said, the customers appreciate height. Our local supplier doesn't carry anything taller, or we would get them. I'm going to ask them about the hinged ones Mark was telling about, they sound great.
I worked for years (oh god, decades) in Maine, and like Helen, we didn't carry any easels, the funeral homes all had very nice, sturdy decorative ones. We made the sprays, flat on the bench, those were the days! We didn't do many easel sprays, it seemed that mache's and baskets were the regional fav's.