Take you're time and do the research on these. Read others' opinions in other threads here and on Large Format Forum.
There are always monorails for sale here, on other forums and on eBay.
However, as I wrote in my first post, the lenses are far more important than the box they're strapped to. They're not electric, they don't have motor drives, they don't have meters etc.
Pardon the pun, but focus on lenses, not the camera.