First of DamnthePants
I do not have any experience with the type of thing that you are doing, however I can say as someone who has been wearing kilts on and off for 5 yrs now, and everyday for the past month or so you have little worry about kilts being constrictive, on the contrary they allow the wearer to move, think about competitors in the highland games.

As far as places to get your kilt for these activities I would think that a casual kilt from either
USA kilts
www.usakilts.com
or Canadian Casual Kilts
www.canadiancasualkilts.com
might work or you could look into
Sport kilts
www.sportkilt.com
Hope this helps and again