just wondering, whats the deal with middle weights at the minute?

i've got a pair of wheel chair motors with gokart wheels attached and a ton of other parts and i fancy making a middle weight flipper to have a bit of fun with.

im ment to be doing my heavy atm and more than anything its a pain working on it cos of a lack of space so im only doing things to it every so often but i wouldn't mind making a middle as im getting some free time to do something robot related comming up.

just wondering how many other middles are about atm?