Well i eventurly got around to trying the summersault with the unicycle off a trampette. I still need to get another strap for the harness so i can actually jump with no hands.
http://www.boateng.unicyclist.com/summersault.wmv
If you want the video in any other codec ill do it for you.
Trev
Re: First Summersault try!
Right on! Once you land that, what about a barani into a backwards ride? Might actually be easier to land than the front because you don’t lose sight of the ground.
One problem with a Barini is that the uni will hit the actually safty harness im also attached to… once ive worked on the summersault fully ill give the barini ago.
Trev
Well from both the video and your description above, it sounds like it’s that pesky safety harness that’s at the root of your troubles. Helmet, cup, leg protection…that might be all you need. And if things don’t work out, Nurse Trixie’s always here for you.
yeh i know the problem… all i have to do next is move the things further away from the point of the harness 
ill be trying it again on Sunday hopefully so ill see what happens.
Trev
I did a full summersault and landed it today took quite a bit of effort but the key to this was the safty lunge was stopping me rotate last time so I moved further away I think ill have a video on sunday or someday soon because im doing this trick in a performance.
Trev