Right handed. Clip irrelevant. Ditto assisted opening. Thumb stud preferred but hole in blade acceptable. Any steel. Up to $150. Minimum Blade length 4.5" MANDATORY. Plastic handles unacceptable. Weight irrelevant.
Do you have an intended use for it?
Cold steel Spartan (plastic over steel liners)and Ti-Lites both meet your requirements as does the Benchmade 13220, but the geometries are completely different. The Spatan's a chopper, the Ti-Lite's a dagger, and the 13220's a mild clip.
http://www.coldsteel.com/folding-knives.htmlhttp://www.benchmade.com/products/13220Spartan

Ti-Lite

13220
