Super Mario 3D Land - Nintendo 3DS ROM & CIA - Download
I saw a post regarding 3ds rom hacking earlier. And to answer some queries, yes you can in fact import custom models for 6th gen rom hacking. You can also be creative
GitHub - davFaithid/CIA-to-3DS-Rom-Converter: Converts CIA (CTR Importable Archive) a.k.a. eShop games or DLC to 3DS (Self-Explanitory) Cartridge Format