I made a pair of 3 seam split crotch pants for Charlie (link for pattern) I used an old pair of pants they are checkered.
This is when i drew the pattern onto the pants
This is the pants ready to be sewn up.
Here is charlie modeling them when i popped them on him to check sizing etc.the split will actually be smaller and not as noticeable he was just wearing a very bulky nappy.
*pics of the final product to come:still got to put elastic in and hem the legs*