chicachina,

why don't you make it a Baltic roundtrip starting in Stockholm, heading down to Copenhagen, flying over to Lithuania (Vilnius) or Latvia (Riga) and then proceed North through the three Baltic Republics into Tallinn and use the ferry to Helsinki in the other direction?
Estonian Air (www.estonian-air.ee or www.estonian-air.com) and AirBaltic (www.airbaltic.com) are worth looking into. Their planes are perfectly modern and well maintained. Also take a look at Air Lithuania (www.airlithuania.lt) and Lithuanian Airlines (www.lal.lt/en). One of those is the state carrier and might be preferable over the other one. I never can remember which is which.

And one more thing: I don't understand yeadonite's post stating that there is very little light during daytime in Scandinavian summers.
Rather the contrary is true. Scandinavian summers offer long days with very little darkness during nights, which may be startling in the beginning, but which offers large oportunities for excursions and very special light experiences. I think it's lovely.

Enjoy
hsv

I found yeadonite´s comment a little odd, too. How can it be dark when the sun dips behind the horizon for only couple of hours. And above the Arctic Circle it stays up 24 hrs for almost two months.

OOPS! That is why you need to proof what you write. I meant in the summer it is light until very late at night, in the winter there is not a lot of sunlight. It took me a long time to get used to constant sunlight.