I'm also looking for a new Rear wheel drive chair options. I'm really having a hard time finding something new too. I don't want to buy another Invacare they are having to many electronic issues. I hate the way there's no way even give Inavacare feedback. I can't stand the way their joystick light blinds you in the dark. I'm over the weight limit for a Permobil My Wheelchair therapist had me demo an Amy Systems chair which has a Hybrid dive which is a like a mid & rear wheel drive. I'm going to give it another try its the closest to a rear wheel drive that's an option that I can find for me.
The Alltrack R series is Hybrid because it combines the best features from both mid-wheel and rear-wheel drive models and packs it all into one wheelchair.