I think it unlikely that Scotland really will vote for full independence once the costs are thought through. Far more likely is a demand for more delegation of powers. That's the real argument.
The West Lothian question is highly relevant. If Scotland decides to split then England has to have a say in how it does it because the deed cannot happen in a vacuum.
A completely independent Scotland would have its own fiscal policy which may differ from England's. That means that sharing a currency would be a bad idea for one or the other. The process of creating a new currency for a country is pretty fraught. It's mechanically pretty easy but would leave the country in the hands of the markets and the speculators, so fiscal freedom may be severely constrained.
There are 27 members of the EU plus Norway and Switzerland. Those two have had to negotiate separate trade agreements with the EU and found themselves on the wrong end of EU-wide legislation that affects them drastically but over which they have little say. Thus there is a case for Scotland to join the EU - except that new members are also required to join the Euro. The lack of a common fiscal policy is the reason for the mess that the Euro is now in, and is eventually going to be fixed. Probably. But for Scotland this means bowing to the EU's policies and this could be a great deal less appealing that sticking with Sterling and its constraints.
Presumably Scotland would take control of the Royal Bank of Scotland, still headquartered in St Andrew Square. Good luck with that, and the establishment of a central bank with full regulatory responsibility for one of the worlds largest and most diversified banks. Scottish banks have rather a poor record recently.
What with setting-up equivalents of the MoD and all the other ministries, a DVLA, an HMRC and building an embassy in half the world's capitals that's a pile of jobs for Scottish grandees, all of which has to be paid-for by somebody. The multi-award winning parliament building didn't set a good precedent. But I suppose Gogarburn might be available: its former use as a mental hospital notwithstanding.
Just be careful what you wish for. The English have done the Scots many wrongs over the centuries, but that is the past. The future isn't what it used to be.
