I've got currently only one midi and I've dumped all of my router accessories into it for now -> need to get organized with it. Will probably fit double amount of stuff in it if everything had a good place and was not in its own box (guidebushings in one box, routerbits in various boxes, Jessem guiderollers in their own box, the oddments of OF1400 and CMS-OF loose bit just thrown in, etc.)
I'm also planing on making a hand-plane storage box out of a midi once I have time to figure out if I can fit all of my planes in a single box. I currently have three in a normal sys-2, but they are too short to have a jack plane in any other orientation than cornerwise which makes for really bad space utilization.
A second set of stuff I'm going to organize in a midi is my sharpening stuff (if it all fits that is) - a worksharp 3000 with a bunch of plates, honing compounds, all the attachment accessories, Veritas honing guide with all accessories, three Eze-lap diamond plates, leather strop at least... If there is enough clearance for the WS3000 to stand up in there it could fit, but haven't tried it yet.
What would be nice is to have a midi with a row of sortainer drawers "under the bottom" i.e. like six narrow drawers or three wide ones for odds and ends with a SYS2 or 3 height compartment above it and a DF lid to top it all off [wink]
My SYS-MFT hosts about the same stuff you have, but just thrown in [embarassed]