Personally, I spent a few years working at a psychiatric research hospital affiliated with a university. We worked on studies of therapies for people with several different mental illnesses, and I was able to get experience with almost every aspect of the research process -- IRB, recruiting, testing, data analysis, paper-writing, etc -- and had a lot of time working directly with patients.
This is what I meant. Yes, some of us actually do coordinate clinical trials after graduation.
(Sorry, really into the smilies today.) The experience I and many of my classmates had is basically this. AlaskanJustin does make valid points -- I too think the most important thing to keep in mind is how you can relate your experience to the lab you're applying to. If they are doing genetics research or neuroscience research that you can directly apply your skills to, you're going to be a very attractive applicant. Also if they are looking to fill a certain niche you may have it. However, if your bench research doesn't relate much to the lab and the direction they are heading in, you are going to have a harder time competing with people who came from labs doing very similar work. Profs really like when you can jump into the lab immediately and get research started without much assistance.
If you have experience helping writing grants, dealing with budgeting and general lab management, managing IRB (fun), recruiting, consenting, and running participants, doing assessments of participants, coordinating interventions/treatments, analyzing the data, and presenting and writing up the results, you are more likely to be able to jump right into research when you get there. Also, with a general clinical RA job you tend to learn time management very well.
So a bench background isn't necessarily a problem, especially if it relates to the incoming lab. It might be more a problem if that's ALL you had and you never had any original input into the studies. I know we look for people who have designed and implemented similar research to what we do and who can be productive from the start. That will vary by program and lab.
If you can't pick up intensive experience super-close to the labs to which you applied, maybe attempt to get some assessment training. That would make you look attractive, too.