Tried making a UT Light Battle Tank with the new SS rules, including the official optional armour density option.
End result is actually pretty close to the stats found in Ultra-Tech.
Changing the (single) 2-PP Tracked Drivetrain to a single system worth of Robot Legs changes Acceleration and Move from 2 yards per second squared & 20 yards per second to 5 & 5 respectively. However, Hnd/SR changes from -3/5 to +3/1. That's an improvement of +6 to Dodge. With Driving (Mecha) of 12, this grants an average Dodge of 9, which is kinda OK; with an ace driver at Driving-16, it becomes 11, which is nothing to sneeze at. (For comparison, a tank will have a Dodge of 3 at skill-12 and 5 at skill-16.)
I'll take a look at the MBT found in HT a bit later.