All very fair and reasonable objections, although I think I should perhaps clarify a few of my points in order to better illuminate my position.
By deportation within the context of my post I merely intended to describe in a generic sense the involuntary physical removal of an Icelandic Citizen from Iceland; although I understand how in the modern legal context it describes the removal of an individual from a country without any fiduciary obligations for the receiving party, as opposed to extradition which is typically contingent on the specific handling of an individual by a receiving government.
What we have to keep in mind however with respect to Article 66. is the fact that it is phrased as "expulsion" with no further clarification whatsoever, which would imply that the right was intended to be absolute in the eyes of the constitution's author. This is particularly apparent in my opinion when other rights enumerated in the constitution, such as the final subsection of Article 66. clarifying the right of individuals to voluntarily leave Iceland, is subject to an explicit limitation; in this case judicial decisions made by a court of law, or a lawful arrest. Therefore the claim that extradition is in line with constitutional processes would be made based purely on the ambiguity of a word which was clearly intended to describe a physical phenomenon, and despite the fact that their is no caveat explicitly mentioned to that enumerated right when other limitations on other constitutional rights are explicitly permitted.
In other countries by contrast where extradition of nationals is permitted, there is either no explicit constitutional protection of the rights of citizens to reside in their country or, in cases such as Canada, a feature within the constitution such as a "notwithstanding clause" or "reasonable limitations clause" which allows governments to bypass some of the constitutional limitations on its authority, subject to some oversight, in order accomplish things which would otherwise be legally impossible in the conventional constitutional sense. In Iceland however, for better or for worse, no such clause exists which effectively renders every constitutional article absolute unless it individually is explicitly specified otherwise.
I understand completely however that there are numerous practical factors which would make the prospect of refusing the extradition of Icelandic Citizens cumbersome for the Icelandic Government both with respect to prosecuting criminals and maintaining cordial relations with its European neighbours. That being said such issues can be resolved through the following considerations which would allow for Iceland to remain a member of the EAW system:
-allowing for Icelandic Citizens to be subject to trial in absentia by the government of the nation in which they engaged in a criminal act, followed by the serving of their sentence in Iceland with all the benefits of the Icelandic judicial system. This would be largely reminiscent of the arrangements maintained by The Netherlands through their participation in the EAW, where their nationals serve time in Dutch jails after being sentenced.
-allowing for foreign nationals to be extradited from Iceland to the petitioning state through the EAW system, with Icelandic courts retaining the right to reject an extradition should they wish.
We should also ponder the fact that wider problems exist within the EAW system which need to seriously be taken into account. Although it protects the principle of double criminality, the EAW leaves the courts of its member countries with little power to prevent the enforcement of an arrest warrant or extradition request on grounds of faulty evidence or the possibility of institutionalized corruption within an EAW member state. This last phenomena has already begun to crop up in the case of countries such as Romania, in which prosecutors have gone after political opponents living in Britain.