The "sneak peek rendering" looks like a YZ250 2t engine in a YZF 250 Chassis.
And the 'Y' piece design / modelling is a common thing used in putting a 2t engine into a 4t frame.
Is this really what this is?
An AFC type conversion to a twin spar frame?
Nothing wrong with that, at all, of course.
Mind you, I'd rather use the 05 / 13 Yamaha chassis with the back bone, single down tube into double cradle Aluminium frame if I were to do a 'different' AF when it comes to other engines - instead of the spar frames. Built with minimal parts and welding, using a variety of construction methods. It's a Very good frame. Both in terms of handling and durability. That has defied some 'experts' opinions about a 'conventional' type aluminium frame not being strong enough. Good design, can negate the need for large section tubing / large fabricated sections / large castings or forgings.
There is no inherent problem with the CS centre to SA pivot centre to rear axle centre with the YZ250. So I assume , if you are moving the engine, for whatever reason, you'll be making it so the CS position is in the same general area. When doing such a thing, you'd be mad not to add in a way of doing SA pivot adjustment / or CS / Engine placement adjustment, if you've made the effort to change so much of the engine mounting.
We may end up seeing production MX / Dirt Bikes being made to take an adjustable Swing arm Pivot 'chip', to allow some further suspension tuning. If mainly / only for marketing reasons, that few will choose to change. It's long been out there on several production road bikes.
Perhaps you will be doing some sort of anti torque set up - or simply a roller set up so as to not stuff up the suspension when the CS has been moved to a less than 'good' position, in the interests of wherever you intend to place / orient the engine?
A twin spar frame, with relocation of fuel tank and air box, could lend itself well to getting the 2t pipe out of the firing line of most of the (all too frequent) damage that they so easily get. That goal might be better served by movement of the engine, I think.
All questions / comments - not criticism.
It will be interesting to see what comes out of this.