I need to build a specialty cutting system, which is focused primarily on vertical table scenarios. Our requirements are 60 inches of X travel. Would it be possible to engineer an LR4 gantry for this span?
Anything’s possible with this community 
What material are you cutting/engraving/laser/plasma or othering? Lighter loads will require no/less mods. Have seen someone cut leather with 60" usable cutting width gantry before, not sure what results they got.
If you need an LR4 to be mounted on a vertical table, that is going to be challenging.
The X Gantry, up to the brace ends, can be built that size. I’ve seen one 10 feet (3048mm) long.
It’s discouraged to make it much larger than 4 feet in span.
The one I know of has a drag knife on it.
I wouldn’t try to do hardwood cutting or carving with that oversize beam.
The problem is as Jason points out, the LR4 Y axis is designed to sit horizontally on a table.
It is not designed to be mounted vertically and will not work in that orientation.
The stock LR4 Z axis also depends on gravity, but if you’re making a custom Y axis you’d also be making a custom Z.
Could a custom machine be made that used an LR4 beam with alternate Y ends? Yes, maybe. But it’s going to be a fully custom machine from that point on.
Curious what type of vertical scenario(s) you’re thinking of?
Horizontal CNC, with horizontal or vertical mounted stock…
Mostly vertically mounted CNC… (can also use horizontal, table optional)
CNC that can be vertically stored when not in use… (cannot operate this CNC vertically)
Wall mounted setup (like a circular saw sled in this case…) …
If you are going to exceed the standard gantry width, you will need to increase the number of strut braces.
As mentioned, the wider the gantry, the less rigid it will be, so cutting hard materials will have some challenges.
I agree with the statements regarding a vertical build - not practical for the Lowrider series. Maybe a Maslow is more suitable. But additional details regarding the vertical table would help us to help you.