Midi atx case

morning all, i need some expert advice. im after an midi atx case to fit in to my entertainment unit but the one i have at the moment is about 2 inches to long to fit in there ent unit. i have searched loads of sites looking for a case which is under 14" in lenght but have not had any luck. im in the uk so a uk site would be good if you know of any.

is there any where i can possible just get a atx shell and maybe customise it or build it from new to my own specs.

help would be appericated.