I would really love to see the Realm Conquest System updated so that it can be used on vBulletin 4.0. I might be even convinced to donate for someone's time!
you are more than welcome to post requesting someone to upgrade the code on your forum. Im sure it will cost, and its ok as long as the code isn't released as a new mod on this forum or any other site without the authors permission. Check with the author of the mod and see if he/she will be releasing a vB4 version.