That's an excellent solution. My console is the basic type (no fridge, etc.) and as long as your holder can be turned around to insert either way (just thinking about so it could be setup with phone slot forwards), it could almost be semi-permanently secured to the front of the console structure with a simple bracket and screws so it won't come loose when off-roading.
I dunno if the gearstick would interfere with a large cup if your holder is fitted the other way around in a standard Aus-style (diesel + manual + non-fridge console) 80 setup. Who cares though - you're concept fits the space and looks almost like it's a factory accessory.
Most Oz 80's have the grey interior though the other style (brown) is fairly prevalent too.
See if you can link up with the Witsend folks and get commercial production going as there are no really good cupholder solutions for 80's currently. Din slot ones are hopeless IMHO. So silly that Toyota never thought to the future and actually created a factory console design with twin cupholders suitable for large coffee cups.
This is my 80 a week ago when I was finalising the installation of new Trufit vinyl flooring, underlay and resomat in the front footwell area. The metal bit and rubber boot around the gearstick and transfer case selector are factory parts, and you can see the fugly standard cupholder that Toyota supplies with the basic consoles. LHS of the drivers seat back is right up against that so it's a really awkward place to have a drink!
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Craig.