The Scottish Currency Question

If Scotland decides to leave the Union, what will it use as its currency? As an independent sovereign state, it can't use sterling. Because it won't immediately be (if ever) admitted to the Eurozone, it can't use the euro. Scotland will therefore need a new currency - let us call it the 'dram'. Drams could be issued by a new Scottish central bank and drams could simply have a floating exchange rate or a fixed exchange rate with sterling. Alternatively, Scotland could return to its historical roots and have a multiple reserve system, whereby multiple banks issue their own 'dram' notes, which are convertible into a precious commodity such as gold or a commodity bundle. This keeps the currency out of the hands of Scottish politicians, which may or may not be a good thing depending on one's perspective.