How about a rolling wire shelving unit? You can put your machine on a tray to keep the feet from going through the wires. Plastic tubs for projects and tools. S hooks to hang rulers and mats off the side. Sew up a slip cover to throw over top and roll it anywhere you have space while the dining room is in use. You can find a pretty sturdy chrome unit with 2 to 5 shelves (how much do you need to hide?!) Roll it right up to your table to unload the machine when you're ready to sew and all your stuff is right there. They go together easily and come apart for storage when its not needed.
Disclaimer!!: I have a dedicated sewing room, so maybe my idea is nuts, but I thought it might work. I do let my occasional guests sleep in the bed that takes up space in my sewing room! I try to think of it as a mannequin for quilts! I use my kitchen island to do my cutting as its easier on my back.