I'm not sure what you mean by the Mark V line. There's no such thing. I can only guess you're talking about the 1D Mark IV which is in that price range, but no one is really using that much for video. In the world of DSLR video, the main players are the Canon 5D Mark II, 7D, 60D, t2i, Panasonic GH1, and GH2. But even the t2i starts at $700.
Based on his budget of $500 I'm willing to guess he knows what kind of quality to expect at that range. My recommendation to the OP is to look at how seriously you want to get into film making. Is this something you're looking to do just pass some time as a hobby, or is it something you'd like to get into more seriously down the road? If it's the latter, then I'd recommend saving up a little while longer. Try to get into the $2000 range. From there you can get a pretty good video camera new or used, or it's a decent starting budget in the world of DSLR video should you choose that route.
Also, Panavision cameras don't rent for $28,000 a day. I'm not sure of the exact going rates these days, but their flagship camera (Genesis) rented for $4,000 a day and that was well over 5 years ago.