Fiddled with a midi the other day and its basicly an oblong systainer for *that* slightly longer tool that doesn't into a regular one but still can stack with a normal systainer, albeit it will protrude at both ends since the T-locks align at the centre.
Still kinda prefer the maxi systainers idea with double trouble systainer connectivity, but wish they would make a 'midi plus' systainer with double T-loc latches and double systainer width to accomodate two normal systainers on top of a midi+ systainer with aligned box ends. (Think two systainers glued to each other endwise)
It was unfortunate that my grinder was too large to fit into a midi so didn't buy one even thou it was on sale. Should have bought one just to experiment.