Another option is a hammock. One of the best is the Blackbird:

http://warbonnetoutdoors.com/blackbirds.php

combined with Big Mamajamba tarp:

http://warbonnetoutdoors.com/tarps.php

The tarp can be use separately on those occasions where the hammock cannot be hung. Another popular make of hammock is Hennessy:

http://hennessyhammock.com

My last two tours (NC mountains and Banff/Jasper parks) I used a hammock. To get some ideas of hammock camping, have a look here:

http://www.hammockforums.net/forum/index.php