Joining the single currency is a complete no-no for a start, it’s rare to hear even the most pro-EU people advocating that. For a country which has relied on monetary policy for the last generation, I don’t think losing the ability to control that would be viable. It would only work if our economy was completely and permanently in step with the rest of Europe. This has hardly been a resounding success thus far in the single currency’s history.
And from a political perspective, having to sign up to Schengen or losing the rebate is hardly going to be attractive to people.
Monetary policy has always been a pretty useless lever for us at the best of times, and has reached the point of virtual irrelevance over the last 10 years, with near zero interest rates and billions in hapless quantitive easing being powerless to stimulate a fairly moribund economy while inflation has been an ever-present threat which we have no ability to react to.
Whilst Greece has taken a battering, they may actually have been in a lot more trouble with a floating currency, since the rest of Europe would have had less incentive to bail them out, and some (in the case of Greece) quite badly-needed structural improvements to government finances would have happened later. We wouldn't have had any of these issues at all, since we've been running much more closely to what the Euro requires anyway.
Most people don't push the Euro because, as has been rightly pointed out by others, it's fairly easy to avoid if you don't want to join, and because it's an argument that's not worth having. Pointing out that joining the Euro isn't actually a problematic thing to do isn't particularly controversial though, and wouldn't cause most informed people to lose sleep.
In the case of Scotland, if you think Schengen, the Euro, rebates or anything else would stop us from joining then you don't really understand Scotland.
On the question of whether the EU would accept a rejoining UK or a newly independent Scotland, that isn't something anybody can predict with any certainty. A large country on the edge of the block that hasn't diverged significantly from European standards though would seem to me like it was worth making a special case for, and in the case of an independent Scotland it would be worth doing just to further rub in the costs of leaving. Either way there is nothing that would damp down demands in the UK to get the ball rolling and rejoin.
