Yes, if you incorporate you can get a USD account, you can also get a CAD account. But you cannot sign up customers. The account will be used for transactions happening outside Canada and the USA. You cannot sign up a Canadian or US customer.
If you have a Canadian account in the US, then you can pick up a Canadian customer if you are licensed with FINTRAC.
If you have an AUD account in the EU, then you can pick up an Australian customer if you have an AUSTRAC license.