On the site
http://artists.iuma.com/IUMA/Bands/Richard_Naslin/
there is a "trallpolska" (Trallpolska - LappNils polska a. Erik
Nilsson - 0.71MB). I'm not an expert in Old Norse metres, but I
suspect that the model metre used may be archaic (just guessing here -
maybe there is no detectable metre at all). Or am I just trying to
catch an imaginary butterfly?

/Sjuler