Hoyt Ultrasport and Ultramag would by my suggestions. They can be had for around 400 bucks I think and shoot excellent. Very comparable to the hoyts that cost twice as much or more.

You could also look at the midpriced dartons, they are nice for the money. Or a Parker huntermag. Keep in mind the less expensive bows are not going to be perfectly shock free and spit arrows out at amazing speeds. If you want the best of everything it costs some coin my friend. Also don't go by what a bow feels like bare in a show room. After adding a decent stabilizer, some limbs savers and string silencers most bows tame waay down. Also the proper arrow makes a difference as well.

As for the shorter bows. I own a bowtech mighty might at around 31 inches and it shoots pretty good for me. I am small though. If you can get used the string angle they shoot pretty darn good. I think it is because of the longer risers. I have a 35 inch darton, a 37 inch martin and the 31 inch bowtech. The bowtech has shorter limbs and a longer riser (4 inches longer!) then both the other bows. I think this is why they shoot just as well. The longer riser helps them feel more stable in your hand. I actually shoot the small bowtech better to be honest.

And I think diamond is made by bowtech now, am I right?

And reflex is basically a hoyt, so you can't go wong there either.

Good luck,
Paul