The old Razer DeathAdder has a similar shape and a dpi step of 900, not sure if it defaults to 900 or 1800 out of the box tho, so you may have to use drivers as there are no physical dpi buttons.
If you can find the old G400 model, newer than the first batch of prediction model but not the s version, that should probably suffice, it has a somewhat similar shape, default dpi of 800, which is a bit lower than you want, but one of the few alternatives I can think of.
The EC1 Evo does have a dpi step of 1150, which is fairly close to your desired range, are you sure you can't just compensate for the dpi in ingame sens?