So, after spending years frustrated with no factory cup holder in my 92/93 convertible, I did my own. Simple, really cheap and it works. See pics below and try your own version, but this was my process.
1. Find a plastic hanger-style holder at local retail autoparts store, matching height of the cup portion to the depth of the console inner tray.
2. Cut the hanger part off, leaving just the holder.
3. Select a spot in the inner tray and put the holder in. Drop the lid to make sure it clears it when closed.
4. Use 2 tiny self-tapping flathead screws and screw it directly onto the bottom of inner tray.
5. Close the lid to check clearance again and you're done! SIMPLE!

side view

top view

closed lid

 

So you have to keep the lid open when using it? Let's hope the lid doesn't flop down while driving and knock over your drink. How easy is it to access your drink while driving?

 

This is my answer...

 

Mine...

 

I'm with Jagboi. If you're gonna get cup holders, why half-a$$ it? Just commit, do it, and do it right.

 

where did this one come from?

I respect the simple solution that works for 92/93. Nice work.

 

That was my first thought,

 

It's from a 95-97 XJ6. Here is the XJ6 armrest lying on top of the XJS armrest. It is longer and blocks the window switches.

 

This comes out of the XK8 XKR... I have one in my xk8 and r and I never use it. Americans go big I guess, I have never found a beverage that really fits in it AND having things that I have found fit, really really get in the line of the forearm while driving. You'll need your elbow on that side kinda pinned to your waist line. It's something that's impossible to explain, but you would know when ya deal with it. More, it's hyper over engineered and is subject to not working well once things go funny with it.

Then, I've seen the ones on the ski slope and these too, are too small for most beverage containers that we here in the US use. I wanna do something about a cup holder but don't know what to do. In both, the xjs and the xk8/r... Frustrating

I also want a little more light (at all times) when driving the xjs at night. Has anyone seen or heard of a modification for the dark spot at the center of the main shelf and surface area of the ski slope in the XJS. I'm all ears...

 

The XJ6 cup holders are rather shallow and "coffee accident" prone. The single one has an adjustable, firmer opening.
I do like the cup holders in place of the ash trays, but I won't give them up because a stogie while driving open air in an awesome convertible, plus listening to Puccini is something you just do not give up, do you?

The wife gets her own stogie ash tray + the best cup holder

 

Jagboi, are those the British Autowood cupholders? What's the internal diameter and depth? I've often thought about getting those, because I don't smoke stogies or anything else (Forcedair, what about a custom job with one cupholder and one stogie-holder?), and I don't live in the Land of the Big Gulp, so it's more likely sensible-sized cans and bottles will fit. But I've heard that they're fairly shallow and so don't hold as well as they could.

 

They came with the car, so I don't know the provenance of them. Diameter is 66mm, 60mm deep. Holds a bottle of water or a can quite nicely, and I have a travel mug that fits perfectly to hold tea.

 

They have sold this on ebay for years. It's s great mod for the car.

 

66.3 mm is precisely the size of the standard drink can, it seems. So that should work nicely, and hold it tightly enough that it won't fall out easily even if the holder isn't as deep as others.
As my ski slope needs revarnishing, and the dash wood is developing cracks, this would be a good time to contact British Autowood, but his website is very much reduced, and he appears to only be taking refurbishment orders starting in (northern) spring next year.

 

Yes, it holds a 330 ml can nicely. The can will rattle a bit depending on the roads if the can is mostly empty, but a small price to pay for having functional cup holders.

 

Strikes me that three slim rubber strips glued vertically and equidistantly around the holder would solve that problem nicely and not look too bad.

 

Or a circle of felt in the bottom would probably do the job too. There is almost zero side clearance for a can, so I don't think putting anything on the side of the holder would work.

 

Series 3 XJ6. I made a ski-slope from 1/8" plywood, covered it with leather, and added two (modified) Tesla cupholders.

 

I’ve talked to the guy before. He can make one any way you like, really. One cup holder and leave the other cigar tray? Sure!

Want a larger cup holder...go ahead and find one, he’ll cut the hole for it. The reason he uses these is that they fit, they have a lip that makes this work, and they are stainless...so they fit the design and will last.

They are really just cup holders that are made for poker tables, I believe.

A word to the wise- he’ll cut the hole, you gotta make sure it’ll fit!

 

I appreciate all the input and comments. My resolution had a major directive though that I think was missed... not to alter the look/equipment of the car, particularly with things "stuck" to surfaces. I went for simple and cheap, yes. After a few trips, I find it works as intended with a small side benefit. With a 12oz can or bottle the lid rest down at an angle that shades the container. In Arizona with the top down it's welcome! And the angle of the lid is oddly a more comfortable position for my forearm while driving.