I'm sure I can't be the first one to think of this, but I haven't really seen it anywhere. Curious to see what people think. The general idea is to stay low tech but minimize/eliminate the task of hauling buckets, which seems to be the hang up for lots of folks. So here, the poo goes directly to where it will be composted. There is a large drum under the toilet, divided into three bins. When one fills up, seal it off and rotate to the next one. In the process the pile gets tumbled and aerated. After the next rotation is can be emptied out the back, having been tumbled twice and composted for as long as it takes to fill two chambers. Interestingly I don't think you would need a crank. Since all the weight gets loaded in the top chamber, it would rotate in the right direction (CCW in this picture) by itself.
Here's a quick sketch of the idea.
I'm thinking there would be a big hinged door on each to remove material, and a smaller door within the bigger door that would open to receive "inputs." Or maybe a screw on lid like on barrels. I'm sure there's a solution. And yeah I think liquid would be separated.