Have a read of the Copy users on private server, including dashboard, inputs, feeds, graphs, etc? thread, This is a topic that comes up pretty frequently but there is currently no one answer.
That thread will hopefully at least make you aware of the obstacles when copying feeds and input processing over to another account. You do have the added issue of wanting to do this on emoncms.org which you do not have access to the databases (directly) and the device module isn’t available either.
you might be able to concoct a clever script to use the input and feed api 's to get the existing info from one account and create inputs and feeds on the new account using that data as a template, but if you are just doing this the once, it will most likely be easier to do it manually than to write the script and get it functioning correctly.
Eventually you might be able to use the sync module to backup and then upload again to a different account, but I don’t think it’s ready for uploading yet.
Bottom line is if you are planning on a commercial setup where you can duplicate account for several clients, you will be so much better off with your own server and using the device module and a dedicated bespoke apps rather than dashboards. I use the device module but I have not yet mastered the apps module, but it is much easier to find a backdoor method duplicate dashboards across accounts if you have access to the mySQL tables.