Since I don't have an optical disc, and no USB thumb drives are available, but I do have a second mac, target disk mode over FireWire seems like the only way to install Mountain Lion (since this 2010 MBP doesn't have that permanent recovery mode in its firmware, and I was dumb and formatted the whole disk, instead of just the system partition, thus deleting the recovery partition).
But I'm thinking, when you install on a local disk on a MacMini, is some aspect of the installation MacMini-specific? After installing from the MacMini, will the OS be missing some MBP drivers, and include superfluous Mac Mini drivers?