Niche Zero is worth checking out, apparently changes through grind size with no wastage. It's a little pricey but about a grand cheaper than the next option.
If you can stretch the budget a little, this stripped down version of the Eureka mignon could be a good option. Grind size is adjusted by turning a little wheel on top of the machine:
I know everyone recommends the iberital mc2 as a good grinder. However I move between grind size quite a bit.
There are reports that it's really fiddly to change grind settings. Can anyone confirm or suggest a different grinder?
Currently using the Gaggia grinder.