I would love to see a challenger. The Abrams however is most likely far in the future for any manufacturer. the main issue is the turbine engine sound. a completely new sound set would need to be made among other issues like turret slew speeds and such. All doable but more work than just rehashing something all ready available. The HE Abrams actually makes a decent RC once the work is put into it. I at one time had a complete parts line up in kit form to convert to better tracks and road wheel modification.