Ceremony or reception or both? How about covered hay bales? Or benches?
How 'rustic' do you want to go? I have seen picnic blankets used for seating which was so cute, but that all depends on your guests I suppose - my 93 year old Grandpa wouldn't survive on the floor!! Lol
I'll see if I can find anything else for you...
Inspiration for your wedding as well!
That sounds like a great idea, I can't wait to see them when they're done!
if you want more inspiration, then check out my pinterest board http://www.pinterest.com/krosa2471/rustic-wedding/
I think your idea sounds great. I am getting married outside and then our reception is in a barn so all our decor for our came stands and candle holders my FI made out of wood