I know, we already have MIUI Rom, but it`s not true MIUI, just a little modded sock rom, an it has nothing common with real MIUI.
We had not had MIUI earlier because we were waiting for working Cyanogenmod to take it as a base for MIUI.
Today we have a lot of almost fully working CM11 ROMs.
So I believe it`s possible to make real MIUIv5 rom. And I hope that great developers, who make today awesome CM based roms for Xperia L, will give us MIIUI!