2004 Rodeo - no keyless entry ?

I've just traded in my 99' Rodeo-LS for the stripped down 04' counterpart. I knew this was (and I wanted) a fairly sparce vehicle - but I was still a bit shocked when the salesman handed me 3 bare-bone keys! I find myself really missing that keyless remote. :disappoin Since the truck already contains most of the neccessary electricals & mechanicals, I'd think it should be fairly easy to rig something up... Any ideas or suggestions ? :smile:

I'm not quite sure how to tell if you might have keyless system already, so maybe you just need to purchase a keyfob on ebay?
-Ryan