Hi David,
This is an enormously important topic, and in a first post it might have been better explore the variety and scope of ethical challenges for scientists.
For example, another key issue is the ethics of accepting public money to support one's research, and the extent to which scientists should have to show that they are providing an acceptable return (scientific output, inventions, patents, well-trained future professionals, and so on) for the funds invested in them.
Having said all that, I agree that scientific papers should be subject to some sort of review (not necessarily peer review) to try to verify the integrity of the data presented. If the manuscript reviewers don't do it, who will?
You may be aware that there have been some interesting and well thought out posts on the "In The Pipeline" blog (Derek Lowe) about peer review, and what it might be replaced with, as well as many posts and even more comments about the worrying increase in the number of publications, including chemistry papers, where the scientific integrity has been found wanting, or worse......

An interesting problem. First, I think ethics is dependent on the person. If someone is going to cheat, the only way of catching them is to repeat the experiment, and even that may not work. In my PhD, I tried to carry out a reaction from Tet Lett., and published by an up and coming chemist. I could not make this reaction work, and I wasted a lot of time on it. Five years later, I read a paper in J Org Chem that explained why not - a very key condition was left out of the letter, probably on purpose because there were a number of other similar letters published that used the method of . . . Similarly, in my view, peer review is not designed to find fraud. I have reviewed a number of papers, and I never try to repeat any of the experiments. All I do is to review what was done and assess whether it would be adequate for purpose, and whether the results obtained could reasonably have been arrived at, and most importantly, is the text clear, i other words, am I sure I know what the author was trying to say. That can be important for papers from young scientists. Strictly speaking, my first paper should have beed returned for revision, as I made two unfortunate errors. The first was the material really should have been for two papers. The second part, which in the long run turned out to be important, tended to get lost in the literature. The second fault was that I left out some introductory material that I thought "everybody knew". They didn't and almost everyone misguessed. What I wrote was good, and I am still proud of it, but how i presented it was not, and that, in my view, is the job of peer review.

On the other hand, in the modern times, I can't see why such papers can't be put on the web and commented on that way. Physics does this with the arXiv, but chemistry seems reluctant to go down this path.