Sweft:  I think you over estimate the depth of thought of your opposition, the argument I hear is simple "Inflation is THEFT!!!" and fractional reserve is just attacked as "Making money from nothing" without really connecting the two as you have done.

That said I don't think your logic is correct in that a commodity money solves a problem with fractional reserve lending.  The key distinction is that their are TWO kinds of money, cash money and debt money.  Cash money is the real thing that acts as a medium of exchange, it is fungible, every unit is identical and once it passes from one person to another its 'history' is forgotten, aka its a bearer bond.  Debt money is not fungible, it is always the debt OF someone and is owed to some else and that WHO always matters, the only relation it bears to cash money is the unit of account which it takes from cash.  But debt money as the name implies CAN be used as money, if I have some IOUs from a reliable person I can trade these to anyone well aware of the debtors credit worthiness at very near face value.

Banks can create debt money and yes they do 'create it from thin air' but their ability to do this is independent of the nature of cash money, it's instead built upon the networks of credit worthiness monitoring, law enforcement etc that makes sure we pay our debts or pay a high price for not doing so.  This gives the would be buyer of the debt a high degree of confidence that it will be re-payed, the higher the confidence the higher the debt trades as a percentage of face value.  Now regardless of if you believe this is good, bad or ugly the amount of this debt money created is going to be determined by repayment confidence and leverage limits (which ever is lower) and not at all on the nature of the underlying cash money.

When you say that monetizing dept by printing money makes them indistinguishable this is not entirely correct, the unit of account is decreased in value and because they share that both debt and cash decline in value.  But the non fungible nature of debt means repayment confidence is always a factor and by reducing the unit of account your making repayment easier and more likely, after a crisis when repayment confidence has crashed it may be possible for lenders to gain by this trade off, they would prefer 80% of dept to be re-payed with money that has lost half its value then for 10% to be payed in undiminished value money.  In general we can always expect a lender to suffer a smaller loss under inflation then dose a cash money holder, because some of the lenders inflation loss will be compensated for by higher repayment rates.