Wonderful idea -- My main machine (my 328) is in a 4 foot cabinet my husband built custom, with a drawer #1 having dowell spools for my thread (just not enough for all the thread), the second drawer holds the attachments, etc.
the third drawer is divided to file patterns (dress patterns), and the bottom drawer holds fabric, etc., but it doesn't hold enough of the fabric, not by a long way! I have three more machines, no four, in the living room-dining room, including a Singer 403, a National Two Spool Treadle, a Singer Featherweight, a Babylock serger, now my Singer 201 in the living room, plus I have a big load of my aunt's stuff packed into my living room-- not a pleasant state of affairs! Good luck to you with all you do.
Jeanette