Nope, this is one of those odd UI quirks of Mac OS X. There are potentially programs out there that will tinker with that, but they will likely end up causing more problems than they're worth when it comes time for 10.6.8 or even just some random security update. It may also cause certain programs to become unstable, because they typically work by altering the program in memory. Sort of like cheat programs for video games, which alter certain parts of the game in the memory, and can cause the game to freeze or behave in unexpected ways.
This is one of those things you would have thought would have been addressed years ago, but sadly no. On the semi-upside, the continued iOS-ification of Mac OS X probably means that the menu bar is likely to gradually be phased out over time. Probably by 10.10 or OS 11, whatever they decide to call it. The upcoming 10.7 already introduces full screen apps, so just give it a little more time for the group that screams bloody murder if something gets moved a single pixel to adjust, then get rid of it. Wouldn't be surprised if in 10.8 they make it something you can toggle on and off, then 10.9 has it off by default, then after that it's just gone for good.