Hi Brent,
I like Bikecad but I could imagine some additional functions.
Is it possible to expand the box with any round corners?
I draw with the box mounting parts like Suspension Seatpost or Speedlifter.
Some modern Rear Carriers and Lowriders would be nice, too.
You find Dimension drawing on www.tubus.com.
Greets
Thanks for the suggestions. I will investigate both these ideas for a future update.