wanting to buy Uhaul type box to fit on dodge dakota

[justicewins]

I need to buy a Uhaul type box of some sort. I've been looking at uhaul resales: 14 and 24' box but I have to buy their truck too. Does anyone know if it's feasable to mount one of these type things onto the Long wheel base 90 dodge dakota I already have?. Just needing it for storage so I won't need to drive it much except to load it up then move it a few times. Any suggestions or ideas?