I've done some digging and the main ideas I've seen floating around are using setuid/getuid and using the Authorization Services (which, for some reason gives me a symbol error when compiling but appears to be deprecated now).
My application needs to be able to request root access (for accessing a raw disk drive) at a certain point, preferably with the OS X authentication dialog (I'm new to OS X so I have no idea what to call that).
Authorization Services is pretty well supported, AFAIK.
Here's a link to a tutorial (with sample projects!) which you can use to launch a small tool in which you can get admin priviledges and then you can call the
setpriority
API on your calling process (documentation linked for you).