Unfortunately I couldn't find a suitable direct replacement. The issue is length and the clevis style bottom as well as spring rates. There are just not a lot of 10.25" eye-to-eye shocks out there period...never mind one with a clevis...or any level of adjustability for a kid's quad.
Length is an issue because ya just can't slap a longer shock in there...at least not without some frame mods as the engine acts as the swing-arm and does not "drop-out" at all (hits the frame). I've read of folks notching the foot rests to get more drop-out as well as cutting & welding in tube where the spine runs vertical behind the engine. I've read of gains in the area of 1" to 1.25"...doesn't sound like much but that gain will open the door to many more shock options. Regardless, you still may find yourself having to swap the bottom eye for a clevis (cut & weld).
There is a Works rear for the LT80, but I've heard mixed reviews and it's not cheap...on there website they still list a part number for it, but at almost $500 I think there are better options. CT racing does sell an extension kit (longer bearing brackets) and a longer rear shock...they will set you back $165 & $390, respectively. The extension kit converts the bottom clevis to round, so I've heard of folks just getting the extension kit and finding a different shock to fit. The issue with the extension kit is that it may place more force on an already (relatively) fragile engine case...so you'd want to look into case supports (aluminum strips welded onto the case).
I did see one called a YES in the UK, but it gave no details. The real issue will be spring rates...these are kid quads and not pit bikes normally ridden by adults...so even if you do find a shock to fit make sure you know what you're buying.
I, because I'm a bit nutty, went down a different path. There is a fully adjustable, re-buildable 10.25 eye-to-eye shock, but it's not a direct fit. It's a Fox Float MXR and it's made for smaller riders (a true rarity!!!). It has round eyes both top & bottom, so I had to modify the bearing carrier and modify the carrier mounting brackets (Like the CT racing bracket, but stock length...I can post pics if you want). I found the shock for $290...and even if it cost you $100 for the fab work you'd still have a far superior rear suspension for less coin (IMHO).
Kinda long winded I know...sorry about that, but no real easy answers for these quads suspension wise.