Well, 9 or 10 months later and the solitaire is still going strong on the same LED. I did two two other similar mods using the little $.99 Walmart aluminum 1xAAA light. I did one with a C0 and one with a B0. Tried the B0 first and it started flickering with about 10 seconds use. Turn it off, then back on... Seems as bright as it was initially, but starts flickering again. I just let it run and it completely died after maybe 2 minutes.
Swapped out the B0 for a C0 and the C0 is still going strong. I don't have much use on it as I greatly prefer the form factor of the Solitaire, but I have at least two charge cycles on the $.99 light.
The Solitaire... man. I'm really surprised it's still working, to be honest. I've probably got close to 20 charge cycles on it. Usually I only use it for 2 or 3 minutes at a time but a week or so back, we had a series of power interruptions and I just killed the main breaked just so the lights wouldn't keep coming on and going off. I got out my 3xRxxH light for living room light and the Solitaire to play with. I had it on for at least a half hour continuously.
I did pick up a lime green Solitaire to do something with... I might try building a duplicate to the original C0 build just to see if it's lost any of it's brightness. I'm sure it has, but it still works very impressively. It's a great 'in the mouth' light. We have two mini barns on our property that don't have power. Everytime I go out there to look for something specific, the modded Solitaire is my go to light. It's VERY useful as it gives plenty of brightness without being blinding... and the part I really love is the huge hotspot. Can't really even call it a hot spot... Just a uber wide beam. Sort of like an L4 on super low.