Fractional reserve banking
There were many proposals put forth around the time of the great depression.
The Chicago plan
Irving Fisher, "100% Money"
Sadly, long out of print - hence the price!
A Program for Monetary Reform (Wiki)
Then in more modern times...
A Fiscal and Monetary Framework for Economic Stability
A Program for Monetary Stability
James Tobin, "The Case for Preserving Regulatory Distinctions"
Creating New Money
New Economics Foundation
The Reform of Banking Regulation
Towards a Twenty-First Century Banking and Monetary System
Submission to the Independent Commission on Banking (UK)
Presenting the American Monetary Act
National Emergency Employment Defense Act
Congressman Dennis Kucinich's legislative proposal