Try a clothes shop that's having a closing down sale and see if they'd sell you their shop rails ? My mother has a couple of them with seasonal clothes on them in their converted attic and they're brilliant. Strong, sturdy and cheap
Argos do a variety of free standing ones. If you want to build them in, B&Q etc do them, just measure the space. You buy the rails and brackets separately.
Had some of the Argos ones a few years back but they weren't very strong. Serviceable enough though. These people seem to sell them also but not sure if they're the same quality as Argos or stronger [broken link removed]
