um... if under the tank is what you're looking for, why not just get a sump... make compartments, use one of them as a fuge, and buy a stand-alone skimmer. you would have a better range of selection and customization.
off hand, i don't know any other fuge with a built in skimmer besides the hang-on cpr. the reef systems you see with fuge and skimmer tucked under in the stand have customized sumps.
but like Froggies said "just get a sump... make compartments, use one of them as a fuge, and buy a stand-alone skimmer. you would have a better range of selection and customization. "
sump - refugium
stand alone skimmer- quality skimmer