Options for basement hopper window replacement 40x18

vetting

I want to replace my old basement windows. However the issue is that the current windows are 40x18 which isnt a normal size. I dont want to spend $200 per window when its just basement windows. I'd rather spend that money to finish replacing my normal windows. What are my options? Would it look dumb if I get a 32" standard hopper and just frame it out with 2x4s and then put trim over the top of it?

Just Bill

Custom sized vinyl basement windows from Metal Ind. are about $125.