Rainman, I'm still too much of a rookie to offer much advice on plant species, but I had a very good experience with Spence Nurseries
http://spencenursery.com/home.html. The web site says they sell wholesale only, but if your order is large enough, they will sell retail also.
I sought them out initially to purchase a prairie seed mix for a 4 acre plot. While there I picked up some flats of water willow and pickerel weed. They were very high quality plants. Once I got the plants home I realized I had thousands, maybe tens of thousands, of water willows already growing around the edges of my pond. It would have been pathetic of me to have bothered with more plantings so they went to waste, and I learned an expensive lesson about plant identification. From previous posts, I'm lead to believe pickerel weeds are not too invasive and add early season color.
Oh, I had great success with the seeds I planted last spring for my meadow of warm season grasses and wildflowers.
