The motherboard in that $500 build is a dead end part , that can never be upgraded with one of the [ very] soon to be released bulldozer cpu's
It might be the best $500 build today but its not good value .
Upgrade the motherboard to a part using a motherboard with a 970 series chipset .
Or if you simply want a smaller case then there are AM3+ micro ATX motherboards that will run BD processors , albeit without some power features enabled http://www.newegg.com/Product/ProductList.aspx?Submit=ENE&N=100007625+600138080+600009017&QksAutoSuggestion=&ShowDeactivatedMark=False&Configurator=&IsNodeId=1&Subcategory=22&description=&Ntk=&CFG=&SpeTabStoreType=&AdvancedSearch=1&srchInDesc=
any of those fit in a micro atx case