The recommended way of solving nested quotations in Norwegian is to use «» for the outer level and then alternating between ‘’ and “”. (Source)

Is it a large undertaking to do this with csquotes?
The recommended way of solving nested quotations in Norwegian is to use «» for the outer level and then alternating between ‘’ and “”. (Source)

Is it a large undertaking to do this with csquotes?
Define a new quote style and add appropriate level tests for the outer quotation marks:
\documentclass[12pt]{article}
\usepackage[T1]{fontenc}
\usepackage[utf8]{inputenc}
\usepackage[maxlevel=3]{csquotes}
\makeatletter
\DeclareQuoteStyle{threelevel}
{\ifnum\csq@qlevel<2 \guillemotleft\else\textquotedblleft\fi}% opening outer mark
{\ifnum\csq@qlevel<2 \guillemotright\else\textquotedblright\fi}% closing outer mark
{\textquoteleft}% opening inner mark
{\textquoteright}% closing inner mark
\makeatother
\ExecuteQuoteOptions{style=threelevel}
\begin{document}
\enquote{Jeg (temmelig hånlig): \enquote{I setter uvanlig pris på Dürer --
først kommer \enquote{Som jeg vil fryse etter solen} og nå sanduret fra Melancolia.}}
\end{document}

\guillemotleftwould be expanded before the\ifnum\csq@qlevel<2test is performed. Happily, the expansion of\guillemotleftdoesn't start with a digit: you can guess what would happen. The spaces I added will be ignored. – egreg Jul 23 '12 at 14:24\tw@instead of2? – lockstep Jul 23 '12 at 14:31\tw@is unexpandable and TeX just fetches its value. – egreg Jul 23 '12 at 14:34\MakeAutoQuote{«}{»}in your solution makes it easier to use since you can write«some text»instead of\enquote{some text}. – lalebarde May 07 '14 at 07:28