The Scottish LibDem leader said he wanted his party to work with Labour and the Tories on a common proposal for their 2015 General Election manifestoes.
The move is intended to counter SNP claims that a No vote in 2014 would halt or erode devolution and deny Holyrood the extra powers most Scots say they want.
Setting out the plan in his speech to the LibDem conference, Rennie said: "To win big, people want to be assured that No to independence doesn't mean No to change. So I urge Ruth [Davidson] and Johann [Lamont,] to start the dialogue with me and others on a new package of reforms, to be put to voters in the 2015 General Election. But the SNP has a role too. If they lose the referendum, will they join the discussion, to develop a sustainable model for the UK? It's an open, genuine offer to the SNP. When you are ready, we'll be ready for you."
His spokesman later admitted other parties had yet to be approached, but said they would sit down next year to discuss new powers. However, an all-party group on greater devolution is already being formed at Westminster. Last week, the LibDems published a template for home rule for Scotland within the UK. However, it gives Holyrood more powers than Labour or the Tories would currently concede.
Other parts of Rennie's speech to around 250 delegates seemed guaranteed to antagonise, not woo, the SNP leadership.
Referring to Salmond's decision not to meet the Dalai Lama when he came to Scotland earlier this year after assuring the Chinese ambassador the trip had nothing to do with his Government, Rennie said: "I was embarrassed by our Scottish Government's treatment of the Tibetan spiritual leader. I met him. Nick Clegg showed him respect. Even David Cameron took time to show his support.
"But our First Minister, he slithered, he jabbered, he blathered, he made every possible excuse to avoid the Dalai Lama. He's skulking around under orders from the Chinese Government. I was annoyed; Scots were disgusted; Alex Salmond should be ashamed."
An SNP spokesman said: "The LibDems have been proposing home rule for 100 years – how many more talking shops do they need?"
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