You could definitely write a similar game or an outright clone of LBP for 3DS, similar to the PSP installment. Otherwise, the 3DS is far too limited in power to fully replicate the console experience of the LittleBig Planet series.
Even the Playstation Vita struggled to replicate the full functionality of the console installments, as LBP vita seems to have been derived from LBP2's engine, albeit with significant downgrades.