Do a DIY Imperial Trellis using the trellis allover stencil from Cutting Edge Stencils via Isabella & Max Rooms.
Make a linen look painted wall with Isabella & Max Rooms.
If you are very clever, make your own stencil with AutoCad and color with Sharpies from HGTV's Rate my Space via Chic Modern Vintage.
Freehand a design inspired by a Fossil catalog using a gold paint pen at Scraplog via Chic Modern Vintage.
Make stripes from electrical tape at High Heeled Foot in the Door.
Don't like black? Try blue tape. Don't like stripes? Try diagonal with colored masking tape at Little Green Notebook.
Get wide silver stripes with contact paper at Apartment Therapy.
The simplest yet - the homeowners put up plain masking tape, intending to paint stripes. But they liked the masking tape so much, they left it up instead at Apartment Therapy.
Have you tried any DIY alternatives to wallpaper?