So I've been pondering this same issue - place to securely place a beverage at night. Being a tinkerer nothing online fit my needs, so I decided to build my own.
I have these perfect little holes to hang something from without putting more holes in the trailer so that was the mounting criteria.

Wandering the plumbing parts at the hardware store I spy these guys - drain pipe adapters and peg hooks - PERFECT!

Cut a couple grooves in the bottom, place it on the arms, hang it from the holes - oooops - the peg legs aren't long enough - darn!

Time to stare at the workbench and sure enough - look at those crimp connectors with the shrink tube ends - PERFECT!


Next up, cut the slots for the pegs - PERFECT!

Except the weight of a waterbottle makes it sag because the heat shrink won't cut it...

No problem - stare at the bench some more, spy the extra tool hangers - perfect width, the welder has wire - PERFECT!

No, I'm not a certified welder...

Wa La! No-Drill cup holders! Easy peasy lemon squeezy!!!

Note maximum lean angle on "typical" beverage:
PERFECT!

Hope you enjoyed that as much as I did writing it!
