Here are two singleplayer missions, one for GDI and one for Nod, that I've made quite a while ago using XCC Editor. A brief description of each mission is below:
Winter of Discontent
This Nod mission starts with your base being utterly decimated by GDI. You've got to retreat and regroup, then take your revenge on them using their own weaponry. I made a winter theater mission for Nod, since there are no official winter missions for this side.
They did it again! Nod captures a GDI base in Winter of Discontent
Rescue and Retribution
This mission was inspired by its namesake in C&C Renegade. Using a Commando and a small attack force, you need to break through Nod defenses and rescue civilians from a Nod Detention Center.
The village had been cleared of Nod militants, and tanks arrive to assist the Rescue and Retribution
The mission files are provided "as is". I'm sure you won't have any trouble launching them There are also text files with more detailed briefings, to compensate for the absence of briefing cinematics.