Anyone want to help me design a velociraptor bike?

In a word (or 2), compact geometry.

What you have hit upon is something that has troubled frame builders and short riders for years. For any horizontal top tube designs, you start to reach a point when you;

• can't make the seat tube any shorter because the head tube becomes non-existent,
  
• can't make the top tube any shorter because of toe overlap and the front tyre hitting the down tube.
  So you end up compromising by having steep seat angles, shallow head angles, extra fork rake and very short stems and seat posts, all of which compromise handling and make the bike look weird. Or have smaller wheels.
  
  

Compact frame designs allow a seat tube as short as is necessary with a sloping top to shorten reach without compromising frame angles or fork rake and allowing decent tyre clearance and sensible stem and seatpost length, whilst keeping 700c wheels.

Or something like that :-)