I would go with the following
(1) And Dvorah did sing, and Varak son of of Avino'am,(S) on that day,(R) saying(S):
(2) In Israel's wild-haired outburst, in volunteering, a nation sanctified Yahweh. Listen, kings, attention nobles, (S) I shall, to Yahweh, I shall sing. My tune is(R) to Yahweh, God of Israel.
(3) Yahweh, in exiting Sa'ir, in exiting Edom's field(S), Earth rumbled, the skies dripping(S) and rainclouds dripped(R) water.(S)
(5) Mountains flowed before Yahweh. This(R) being Sinai. Before Yahweh, the God of Israel.(S)
I extended this to a full translation of the relevant chapter here: http://en.wikisource.org/wiki/Bible_%28Wikisource%29/Judges#Judges_2-4
The point is that this is a militaristic thing, and the word is more of an outburst of military might than an outburst of long-haired hippy-ness.
When I translate a section that isn't already on Wikisource, I place the translation there--- most of the Hebrew there is my translation. I did this chapter to answer this question.
בִּפְרֹעַ פְּרָעוֹת בְּיִשְׂרָאֵל
For the specific translation issue at hand, you want to keep the connotations "wild" and "long-haired", but not give too much preference to either, because of the overlapping Hebrew connotations. My initial consideration was whether to preserve the grammar. In a most literal translation;
In Sowing-wild-hair-abandon-like wild-hair-abandon within Israel
I had a few initial ideas:
- In Israel's wild abandon
- In Israel's wild-tressed abandon
- In Israel's wild-haired abandon
These change the grammar, so that instead of "In verbing noun in Israel", it becomes "In Israel's noun".
The next idea was to make the wildness analogy by using hippy imagery, where long-hair is also a connotation. I searched and searched for good hippy terms, but found nothing (although the abandon business does come from one of the woodstock stories I read while doing that).
Then I considered keeping the repetition, so that it would be:
- In wildly wilding in Israel
- In ruling unruly over Israel
But these are no good, because the meaning is too different. So I finally gave up and used one of the lesser variants. But the meaning is pretty clear--- it's a poetic sentiment for a radical event, involving wild hair, and great victory. The hippy business is no good, because the chapter involves victory in war, so the parallel is not apropos.
I don't think any of these translation considerations really make a big difference to the content of the chapter. I had to translate the whole chapter (and know the surrounding story) to make decent choices, you can't translate words outside of context.