My wife and I recently took a trip to Mt. Rushmore for the July 3rd fireworks and across to Big Sky Montana for a conference. On the way back to Illinois, we swung by
http://www.protatch.com at Grand Island Nebraska and visited a customer who has two of these
http://www.protatch.com/Pontoon15.htm boats. It appeared smaller than anticipated (5' x 15'); but seemed pretty stable. We wound up ordering one and should receive it this Saturday.
FWIW: We became aware of a very slightly used Sea Rider (I think) boat for sale as we were heading out. It would have been cheaper and easier (already had outboard and trolling motors). We didn't go that route for a few reasons; but the two major ones were... It had two large pontoons and owner indicated due to those and a shallow sloping pond bank, she had to bail off a few feet out in the water. The protatch one is supposed to float in 4" of water so it should be much better for shallow ponds. Other big reason was load capacity. That one, though it had a bigger deck, had a stated load capacity of 4XX pounds. The one we ordered had a 9XX pound load capacity. Difference between being able to take 2 people or 4 people. Biggest other reason was that the four pontoon design is supposed to be more stable.
Also FWIW: I had been looking / researching for a number of years. You can even probably find some old posts on pondboss from me seeking advice. I think we'll be happy with the Protatch. They have a slightly smaller version that I had originally planned on; but after seeing it and comparing specs, the one we ordered seemed to make the most sense for us.
Also FWIW: I also have a large (30 foot?) pontoon boat. It is nice for some things; but not for fishing small ponds, hauling around much, etc. The smaller one will still probably lots of stability and the pontoon boat type benefits without the pain.