[kh99]

The page I linked to is not exactly a mod, but is an article explaining how to program your own pages to "add on" to vbulletin. If I understood you correctly you already have an php script and you want to add the vbulletin navbar. That is not exactly what the article describes, but it does show the code you would need to add the navbar to a php script. I think a programmer familiar with vbulletin should be able to do what you want. I'm not 100% sure about the time. It could possibly be done in 1 hour if everything went smoothly, but if problems arise I could see it taking longer.