Yes it can, all have a design pressure and if it is not available commercially you can ask the manufacturer to design one for you.

But if your considering a valve you will constantly open and close, and it is not so big, I recommend you use a ball valve, it is easier to open.

Yes, gate valve can handle high pressure fluids as gate valves are used in fully opened or fully closed condition and not for throttling purpose. there are some good design like back seat sealing which can provide on line gland replacement,Valve trim in s.s. construction and some advance design.

Bonnet construction in a gate valve is pressure seal bonnet. This construction is adopted for valves for high pressure service, typically in excess of 15 MPa (2250 psi). The unique feature about the pressure seal bonnet is that the body