Jeff -
As you've seen here...there IS NO "best" !
Bullpups were originally designed as..."close combat weapons". A rifle that can be easily used inside of a building. "Easily" being the key word.
A true "bullpup" should be no longer than 30", by their "original" design, this include the addition of a suppressor ! The rest are just normal, long barreled rifles with the action behind the trigger ! Or as some call them, semi-bullpup !
In a somewhat order (all of the below are very accurate guns, even to 75 and 100 yrds) -
1. Airmaks, Caiman (or Caiman X), much more than people give them credit for, a very solid gun.
2. RTI, Prophet Compact, another very solid choice. Can be made pretty quiet to keep it short (without the addition of a suppressor).
3. Uragan Compact, Great little gun, easy to shoot
4. FX, Wildcat Compact, Another great gun, easy to shoot
5. / 5-1/2, Daystate, Renegade and Pulsar, Yes, they have a rear mounted cocking lever, BUT, they have a trigger (electronic) that can't be matched.
6. Edgun, Lelya, a solid, tough gun. The cocking is a little stiff. Can be beat around in the bush, with no damage.
Don't forget the newer Cricket II's too. The Compact and the Tactical are also worth a look.
There others but they are over your dollar value.