I'd like to build it larger - to fit over my patio --> Building a Grape Arbor is a DIY project you can tackle yourself. Plan on some work, this beauty will take some time and effort but can be built in a weekend if you get started Friday night!
Kitchen garden inspiration - build an Amish cold frame. I love this clever design. No plans available (our Amish friends didn't even use plans to build our sheep barn), but there are 10 photos in this post showing construction details.