To put it simply, Trust Doesn't Scale.
That means that any system like this that you want to build will stay small. And with small scale systems, it becomes hard to sustain it. The amount of work it takes is a friction that muggle merchants will struggle with. This has also been, I believe, one of the main problems of alternative or complementary currencies. How do they integrate the alternative into their accounting systems, for one thing. And why would someone use this alternative - what advantage does it have? What makes the people running the system keep doing it?
FYI, see
http://www.complementarycurrency.org/ccDatabase/ for a list of these. There's a lot of them.
But money itself isn't the problem. It is the solution. The crux of the issue, IMHO, is that what we are using these days for money is a poor version of it.
Money is simply the one thing that is the most barterable. It is the thing that can be traded that everyone accepts.
The money we use today, in every country in the world, is based on debt. That makes it poor money. We all should understand why debt is bad, but I think Paul's admonition that obligation is poison should be proof enough. But when it is used for money it becomes even worse. Economic debt has interest and that must be paid. But where does the interest come from? If you borrow $100 (a book entry) to print $100 in cash but need to repay $105 - where does that extra $5 come from? If you are the monopoly money printer then the only way you can pay it off is to inflate. And inflation artificially stimulates the economy, leading to overinvestment in production - more factories, more consumption, all for the sake of "growing the economy". This artificial growth is unsustainable in the long run and one of the primary sources of our ecological degradation.
[As an aside, this is why politicians may pontificate that they want to pay off the national debt but never actually do. Even "balancing the budget" is potentially dangerous as it would stop the growth of the currency, endangering a new depression.]
But if instead we use more stable and sound money, based on wealth & production, then the problems caused by debt based money are restricted or just gone. In the past we used gold and silver, which are physically limited and require work (production) to produce. Now we have bitcoin as well, which is limited by math so it can't be changed at the whim of short-sighted politicians.
To put it in more Permies like terms, the Dollar is like industrial farming (pillaging the countryside | inflating wealth away from the people), complementary currencies are like organic farming (trying to do good, but not doing enough), and sound money is like
permaculture (allowing the system to naturally balance itself).
I am currently working to upgrade my Shire Silver to make it hugely easier for merchants to integrate into their accounting and money handling systems, so that can be used now but in the (hopefully) near future it will be a piece of cake. And bitcoin can be somewhat easily integrated into merchants' systems now through third parties like BitPay and Coinbase. These are better and easier solutions that trying to start up another barter network.