What your suggesting isn't possible. If you change the data souce / destination you need to open the project and update the components. Mainly because SSIS is very strick on metadata. When it runs it validates the data sources, tables, fields, data types, lengths, etc...
All that is stored in the package dtsx file and if it doesn't match it won't run. This is why there is no way to specify dynamic data source / destination. This is also why the data flows are so fast.