If there is a gap in existing drywall where the bar used to be, why not just drywall the gap and texture it to match? My bet is it would cost less.
If you want a foam beam, someone just advertised their product on here a couple days ago, although I hate to promote that kind of thing (advertising without a question...)
Those are my suggestions, with what little information you have provided. Get some estimates from some local drywallers especially pick the ones who advertise repairs and phrases like no job too small. Look under "drywall" in the phone book.