Given that many of us post commercially oriented websites into this forum on a very regular basis, have you ever run a poll on banners/advertising.
Have you considered a section like ''Our Readers Recommend'' and fill it full of revenue raising banners. I can think of Joel Malcolm's Aquaponics site for one that has been frequently posted here who may wish to link to this site.
I don't want to step on anyone's ethics or commercial arrangements but bandwidth and time do cost and I think we are adult enough to deal with that.
Just a thought.