I've been using a uCurrent Gold from EEVBlog that I built myself from scratch. It has been invaluable down to the nano level for current measurements. I can easily slide it up to uA or mA level. Anything beyond that a Fluke would be my choice.

If you're actually building an application then you can probably reverse engineer the uCurrent to handle larger currents or use an off the shelf hall-effect IC to make measurements as well. Just like Hymie said above you'd likely have to build in some type of analog switches or relays to go between the different shunts. (and then compensate for any additional series resistance added by said analog switches, less important for relays)

 

I've been using a uCurrent Gold from EEVBlog that I built myself from scratch. It has been invaluable down to the nano level for current measurements. I can easily slide it up to uA or mA level. Anything beyond that a Fluke would be my choice.

If you're actually building an application then you can probably reverse engineer the uCurrent to handle larger currents or use an off the shelf hall-effect IC to make measurements as well. Just like Hymie said above you'd likely have to build in some type of analog switches or relays to go between the different shunts. (and then compensate for any additional series resistance added by said analog switches, less important for relays)

Great thanks for the suggestion really valuable info I think thats the route I am going to end up going