A twin size four poster bed makes a wonderful bed for a little girl's room. Twin four poster bed frames with extended posts on the headboard and footboard create an old fashioned, romantic feeling in a bedroom. A twin size four post bed is also a lovely bed to furnish a spare bedroom. For a larger guest bedroom, create a suite with two twin size four poster beds for overnight sleeping accommodations. Single size four poster beds is another term for a twin four poster bed.