Because you commented in the thread, I decided to check the dimensions of the Lexus drive axle. It's 16" overall and 11" from the axle line to the rear mount. The framehead in the Beetle is 11".
So I'm thinking a Superbeetle/Rabbit macPherson strut would work better. It fits better with the monocoque tub anyway.The altermotor (the part I don't have) could be supplemented with solar panels.
Reposted from another thread. Give it a squareback roofline and it's long enough for a pop-top camper.