The conventional wisdom about the impending Lib Dem meltdown in Scotland is that they'll cling on in at least two seats - Orkney & Shetland (because it's been a fortress for the party since time immemorial) and Ross, Skye & Lochaber (because of Charles Kennedy's personal vote). But it should be borne in mind that the 'Kennedy bonus' is already factored in to the Lib Dems' baseline vote in his constituency, so there's no reason to automatically assume the drop in the party's vote will be lower there than anywhere else.
Newsnight have recently introduced a regular prediction 'index' for the general election, using the same figures that appear on the Election Forecast website. I suspect that will prove rather awkward for the BBC, because it means they'll be openly acknowledging that the party they'd like to ban from the leaders' debates is on course to become the third largest party in the UK parliament, ahead of the Lib Dems and miles ahead of UKIP. But Election Forecast also produces predictions for individual constituencies, and is currently showing that Ross, Skye & Lochaber is the fourth most likely seat to be gained by the SNP, with a probability of 98%. Charles Kennedy is predicted to receive just 24% of the vote, compared to the SNP's 50%. That would represent an enormous 31% swing from Lib Dem to SNP since the 2010 election.
What's interesting about this is that the constituency predictions are seemingly not based on assumptions of a uniform national (or even regional) swing, but instead on unpublished YouGov subsample data at the constituency level. Admittedly, some of the other predictions don't really pass the smell test. Plaid Cymru are predicted to lose one of their three seats, whereas I think it's much more likely that they will hold what they have, and on a good night might regain either Ceredigion or Ynys Mon (or possibly even both). So it could be that the constituency sample in Kennedy's seat isn't representative - but the point is that it would have to be inaccurate by an absolutely huge margin for him to have a chance of hanging on.