I gave this a shot, and got some. Err, interesting results to say the least.

Dose: 1 small coke, about 34 mg
Bedtime: Around 9 o' clock.
Dose time: Around 8 o' clock.
Technique: DILD
Supporting Supplements: 1 cup apple juice [10 minutes before falling asleep]

And I got this: I don't even know anymore... - Dream Journals - Lucid Dreaming - Dream Views

It was amazing, and weird, and I don't even know. But I have my assumptions that it was because of the caffeine. It got 10/10 vividness, it felt like real life without any question. It was one of my longer dreams, and it was a dream inside of a dream.

Definitely trying this again tonight, see if I get any better results.