http://www4.jcpenney.com/jcp/ProductsHOM.aspx?DeptID=25437&CatID=25955&CatTyp=DEP&ItemTyp=G&GrpTyp=STY&ItemID=0ef2e3c&ProdSeq=3&ProdCount=56&Dep=window&RefPage=SearchDepartment&ShowMenu=T&ShopBy=0&SearchString=flatform+bed&S4DeptID=25437&CmCatId=SearchResults
This one's probably not all that well made (says it has a "paper veneer" - not sure what that is...), but it looks like what you want...
http://www.target.com/gp/detail.html/ref=br_1_5/601-6589672-8406536?%5Fencoding=UTF8&frombrowse=1&asin=B000CPCM2C
This one looks better made, but it's a twin size:
http://www.target.com/gp/detail.html/ref=br_1_9/601-6589672-8406536?%5Fencoding=UTF8&frombrowse=1&asin=B0000DHR7V
Hey, here's the same thing in a full size:
http://www.target.com/gp/detail.html/ref=br_1_8/601-6589672-8406536?%5Fencoding=UTF8&frombrowse=1&asin=B0000DZHG9
That one might work for you... Don't forget the cost of the mattress.
Others:http://www.target.com/gp/detail.html/ref=br_1_13/601-6589672-8406536?%5Fencoding=UTF8&frombrowse=1&asin=B0009PQ7IK
http://www.bedroomfurniturenmore.com/South-Shore-3159-23X-Platform-Bed.htm
http://www.bedroomfurniturenmore.com/Modus-SPL-Simplicity-Platform-Bed.htm