Moves to hand full financial powers to Scotland have been ruled out by the body considering reforms to devolution.
The Calman Commmission said devolving full fiscal autonomy would be inconsistent with the United Kingdom.
The finding came as the commission, set up by Scotland's opposition parties, delivered its first, interim report.
Its chair, Sir Kenneth Calman, also dismissed criticism that the report drew no detailed conclusions, insisting it had been a serious piece of work.
He said some issues had come through "loud and clear" in the evidence, including a feeling that, while devolution had been a great success since it came about in 1999, functions such as defence and national security could only be dealt with at a UK level.
And he said financial issues, such as the devolution of tax powers and the block grant which Scotland gets from the Treasury, would be looked at in future.
But he added: "Full fiscal autonomy is inconsistent with the Union and we do not consider it further."
The commission said a number of areas had been flagged up for further consideration, including whether issues including broadcasting, firearms, energy policy and the misuse of drugs should be overseen by Westminster or Holyrood.
The report was welcomed by Scottish Secretary Jim Murphy and the Scottish Conservatives.
Scottish First Minister Alex Salmond, who is currently conducting his own "National Conversation" on Scotland's constitutional future, dismissed the report as a "constitutional mouse" at a time when he said the powers to build a "lion economy" were needed.
Scottish Liberal Democrat leader Tavish Scott urged the commission to produce a final report which would provide a "blueprint" for Scotland's future.
The Calman Commission, due to publish its conclusions in 2009, released the interim report after seven months of work, involving more than 160 written submissions and more than 30 oral evidence sessions and public sessions across Scotland and in Newcastle.
Sir Kenneth told a media conference at the Scottish Parliament: "We've had quite a lot of evidence already. We do need some more before we come to any final conclusions."
But he stressed: "We haven't been wasting our time, I don't think. This has been a very serious deliberation on Scotland's future."
The independent commission was set up after winning the backing of Scotland's pro-union parties, Labour, the Tories and the Liberal Democrats, in a Scottish Parliamentary vote.
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