titch, I'm not sure which modelling software you're using (did someone say 3Dmax?) but I'd strongly suggest looking carefully at where the compressive and shearing forces are going through your frame.
I am not an engineer, but I am a professional bike mechanic (Cytech 3, for those to whom it matters!) and I've seen a lot of broken frames and analysed how they've broken: the point where your rear shock attaches to the seat tube looks incredibly weak, to me. If you're planning on a bolt-on collar, it will need to be exceptionally strongly clamped, or any compressive force will simply twist it around the seat tube. Your seat tube will need to be strengthened in this area to withstand both the clamping and twisting forces. Don't make the mistake of thinking that all the force from the rear end compressing will be absorbed by the rear shock; the shock needs a solid mount point at both ends, if one of them is weak then it will not compress, just transfer all the force into the mount point and twist it round the frame.
I don't want to put a dampener on your design, I'm interested by your process and I hope you come up with something innovative and functional. But I also hope we can all give you the benefit of our experience, as well as some encouragement.
'one-legged' fork designs can work because there's a strong stable mount point around the head tube and front hubs can be built with big bearings, so the compression forces that would twist the wheel sideways can be minimised. I used to have a USE S.U.B. fork and I was surprised how strong it was and how well it tracked - very stiff.
The problems I foresee with your 'one-legged' back end design stem from the twisting forces that will be created by suspension compression and by pedalling force. Your frame simply does not look strong enough to withstand these forces: the pivot by the bottom bracket seems very small, although the 'beefed-up' chainstays may help withstand the twisting force, and the top mount design on the seat tube seems far too weak, as I mentioned earlier.
Again, sorry for putting such a downer on it, I mean no offence, I hope this is constructive criticism and gives you some points to work on! All the best,
Pete