6″ is more than enough
Well it has been a couple of years since I first came up with the idea of building a short travel bike . lots of time spent on auto cad working out angles geo and clearances, originally I had planed to get some plates CNC cut and have the swing arm as a bolt together unit but as happens I kept putting other (paid jobs) ahead of this build . I have been working on a new suspension frame design with a good mate who is a gun when it comes to suspension design so I figured now was a good time to revisit my half finished frame re working the swing arm design to be more in tune with the style of frames I am planing to build in the future. To this end I learnt a lot and I’m very happy with the end result, I’m looking forward to seeing how she performs on the trail.
Stay up right 
Hey Tarn, can you describe your bottom bracket pivot a little? is there a bushing in the frame? is that an inner shell acting as the axle and removable?
Hi Daniel
This design uses press fit cups (same as the American Bmx bb size ) there are 2 in the main frame and 2 in the swing arm with spacers to keep everything where it should be.