DS Lite? Yes. DSi XL? For sure. 2DS XL, 3DS and its New and XL variants? You bet. But not a single 2DS aftermarket shell. Single backplates are sold here and there but not the whole assembly.
What gives? Is the 2DS really that niche compared to its siblings?
Yes, it sold in much smaller quantities than a lot of those other devices.
Also, the 2DS shells were designed to be more durable. So it’s pretty common for the screen or electronics to die, but the shell to be perfectly serviceable for reuse.