I think BootCamp will probably be accepted by law schools eventually, since as you point out, it's a dual boot configuration.Check with the school you'll be attending. I know where I go, some of the Vista machines have had issues connecting to the network.
The dual-boot info was correct. Some exam software that locks you out of windows (eg., ExamSoft) won't lock you out of everything if you use a mac. This is the reason macs are generally banned from exams regardless of how they're configured -- the IT people aren't going to want to check every machine while setting up an exam to determine how "legit" the dual boot config is.
Do you know what specifically won't be locked out using XP via Mac? I was always under the impression that one booted into XP-- it's not like it's virtualized, it's a real working, full version of XP. Shouldn't it act like a real version of XP?
Another reason lots of schools aren't allowing Macs are bc BootCamp is also in beta. But OSX Leopard should be coming out fairly soon...
Virtualization software will end up being more popular though, since who wants to reboot? Most of the people I work with have switched from BootCamp to VMware Fusion or Parallels, and THAT would allow a lot of exam software loopholes since it's basically just Windows in a compartment. The exam software wouldn't even be aware there was a Mac behind the scenes , "outside", that could potentially access a whole world of disallowed items.