Here is a one piece custom bell for Eb trumpet.  This was made by a well known American custom trumpet builder but it got some dents in it and was replaced before finishing the trumpet.  It never got engraved.  It is cut for a tuning bell setup.  There are solder footprints at the small end and on the side for the tuning rail.  There are a couple of good sized dents and some smaller nicks but all should be pretty easily repairable.  I gave it a hand polish for the photos.  If I hold it upright with the bow resting on a table, it measures just a hair over 17" to the edge of the bell.