We recently (2000) had the introduction of a VAT tax, known as Goods and Services Tax in Australia, on top of normal income tax and other statutory taxes such as Medicare, CGT, fringe benefits etc.
I really do not think it would work on its own. Some sort of income tax is typically essential as they are progressive taxes which have the effect of taxing rich people more. A flat tax such as VAT tends to work regressively, since people with high income are taxed less for any given item. They definitely earn more but that does not mean they definitely spend more.
Secondly, with any taxation, regulatory and enforcement bodies are required to ensure the correct monitoring and enforcement of taxation. Yes, there are a lot of costs associated with that, and many hours wasted. The IRS would still be required for monitoring company taxation, anyway.
Additionally, consumption is, if I recall correctly, an important statistical figure for economics, and introducing something that will retard spending isn't something to be taken lightly.
Yes, the whole tax system is overly complicated and a massive burden on an individual. I just hope eventually we do away with needlessly complex taxation laws and move towards streamlining the measurement and payment of tax.