Bad idea, because it's fairly useless. Basically, you just break up the sale of certain items into parts to drop the tax rate. Want to buy a $20,000 car? No problem. Just pay for a $5,000 chasis, $5,000 engine, $5,000 for interior, and a $5,000 bill for assembly, and you've dropped your tax rate.
To the extent that it could work without being avoided (see above), it also gives a tax advantage to buying cheaper models of the same type of consumer goods, which means it encourages the production and consumption of lower-quality, less durable goods. Just like giving tax breaks for small businesses to purchase SUV's creates an artificial incentive for consumption that is otherwise stupid, tax incentives to buy cheaper goods is an artificial market distortion, and we can expect that the results of it won't be beneficial.
More generally speaking, though, you cannot hope to replace the income tax with a sales tax. States which have instituted sales tax rates above 12% consistently find massive avoidance of that tax, and the problem only gets worse as higher rates. The necessary rates for a sales tax to replace the income tax would be much higher (20% and above) - avoidance would be crippling. And even at low tax rates, there's always problems, because you end up having to make decisions about when the tax should be applied based on definitions of end users of the item, and that's NEVER a simple problem, even with existing sales tax. It doesn't matter too much at low tax rates, but that too will only get worse at higher tax rates.
The only manageable way to do a consumption tax at high rates is a VAT.