Envelope Mode

I would love to use each category as an envelope. Instead of making budgets for income and expenses, I would like to assign money that I earned to customizable envelopes. 
Envelopes should be cumulative. If I save money for a vacation trip, I create an envelope for that and assign some money each month.
Most of the changes would be in the Budget tab. There should be a button on top to “assign money to envelopes”. Money that I haven't assigned yet would be taken from all my “current accounts". So, if I have a new income, the money goes to an account and the same amount appears in the button “assign money to envelopes”. In that case, I would be able to “give every dollar a job”
Maybe it would be possible to have the app working in two different modes. So I could use any profile to work either in the Budget mode (like it is actually) or in the Envelope mode (as described).