NEW YORK (CNN/Money) – As concern over the budget deficit grows, so, too, does concern over the scope of President Bush's proposed tax breaks.

Indeed, many elements of the president's economic stimulus plan, originally estimated to cost $726 billion, will be substantially reduced, if not quashed altogether this time around, before anything is passed into law, say those inside the Beltway. (The price tag Congress now is willing to consider ranges between $350 billion and $550 billion.)

Here's a look at what may get the nod from Congress, as well as what may be nixed or altered.

What Bush wanted: Total elimination of dividend tax for individuals.

Current bet: Total elimination all but dead, but some breaks likely.

In January, Bush called for the complete elimination of the dividend tax for individuals.

That's just not going to happen now, observers say. At this point, said Andy Laperriere, a managing director of the International Strategy & Investment Group, "the range of possible outcomes is as wide as ever."

What's most likely is that Congress will pass a 50 percent exclusion on dividends – that is, half your dividends would be tax-free -- said Laperriere and Chris Edwards, the Cato Institute's fiscal policy director.

A 50 percent exclusion would cost about $200 billion, said Laperriere, who thinks at the end of the day Congress will allow for a total of about $400 billion in tax relief measures.

Greg Valliere, managing director of the Washington Schwab Research Group, thinks even that is a long shot. "I don't even think you get half a loaf," he said. Rather, he noted, Congress may pass a phase-in of a dividend tax exclusion or a phase-in of dividend tax reduction to a flat 18 percent (currently, dividends are taxed as ordinary income, for which rates run as high as 38.6 percent).

What Bush wanted: Acceleration of tax rate reductions to 2006 levels.

Current bet: He may get some acceleration, but not full.

Under the Tax Relief Act of 2001, income tax rates are scheduled to come down in 2004 and again in 2006. Bush had proposed in January that those rate reductions be accelerated to 2006 levels this year.

Congress may choose to accelerate the rate reductions, Edwards said. But since rate relief already is on tap, and given that Congress is unlikely to approve a final package anywhere near as large as the original $726 billion, lawmakers may choose to do so more slowly than Bush proposed, he added.

For instance, Laperriere suggested, it may be that the 2004 rate reductions go into effect this year retroactive to Jan. 1, 2003, but that 2006 reductions would not be implemented.

But, he said, after the dividend tax cut, "the other stuff is really up in the air."

Valliere again disagrees. Rate relief acceleration to 2006 levels is a much surer bet than big dividend tax break, he said. The only wrinkle may be whether Congress decides to freeze the highest tax rate (currently 38.6 percent) at today's levels.

What Bush wanted: To eliminate the marriage penalty now.

Current bet: Undecided on whether he'll win this one.

The Tax Relief Act of 2001 includes a provision that would gradually reduce the marriage "penalty," then eliminate it completely by 2009. Bush had proposed that the elimination take effect this year.

That would mean married couples filing jointly would enjoy exactly double the size of the standard deduction single filers are entitled to. And the amount of income taxed at 15 percent for married couples would increase to twice the amount of income taxed at 15 percent for single filers.

But since marriage penalty relief already is scheduled to take effect eventually, Edwards doesn't think this element will be a high priority for Congress at this time.

Laperriere's sense? "It's going to get squeezed. Something's going to give."

Not so, said Valliere. As with accelerated rate relief, he sees the marriage relief provision as a go.

What Bush wanted: To increase the child credit to $1,000 now.

Current bet: Too close to call.

Parents who earn $110,000 a year or less in adjusted gross income ($75,000 for singles) are entitled to take a child credit. Under the Tax Relief Act of 2001, that credit is slated to increase from $600 to $1,000 by 2010. Bush proposed making that increase effective this year.

As with marriage penalty relief, Edwards thinks such an increase will be a low priority given all the other economic demands on the final package.

Not so, said Valliere. To the contrary, he believes the child credit will be increased this year.

What Bush wanted: To make permanent measures in 2001 Tax Relief Act.

Current bet: Dream on.

Edwards, Laperriere and Valliere all agree: There's no way Congress will approve a move to make the tax cuts in place under the Tax Relief Act of 2001 permanent beyond 2010, when the Act is scheduled to expire.

What Bush wanted: Big expansion of tax-advantaged savings accounts.

Current bet: A no-go this year.

Bush had proposed in January that all IRAs be replaced this year by tax-free retirement savings accounts (RSAs) and lifetime savings accounts (LSAs). Individuals at all income levels could contribute up to $7,500 a year after-tax and have that money grow tax-free. There would be no conditions on LSA withdrawals, and conditions on RSA withdrawals would be more flexible than they are on regular IRAs.

The savings proposals have generated a lot of excitement. But given their long-term costs and all the other legislation on the docket, Laperriere, Edwards and Valliere said there's no chance Congress will give them the green light, at least not this year.

However, Edwards said the RSAs and LSAs are viewed as trial balloons, and they may well be revisited in future tax relief packages. By proposing them now, he said, the White House is "putting a marker down to show where they want to go." So stay tuned.

It still is possible, however, said Valliere, that Congress may increase the contribution limits that individuals can make to their 401(k)s and IRAs.