Is that $30K on electronics or the entire room, lol..
we need to know what the 30K buys, since its a 10K sq foot home, I will guess, speakers and electronics, Screen and projector will be extra, lol..
4 vtf 15h subwoofers.. $4K
have sound scape 8's made with a matching center and pair of surrounds maybe like $17K if you are nice when you ask...
Then to power it I say 3 XPA3's for the front and a pair of xpa100s for the surrounds, just because.. $3300 again call and ask nice...
For a preamp I would just buy a decent denon current model with the options they want... $900
with wires and a panel that should get the job done for under $30K and sound awesome...
good luck, lol...
PS my best advice would be for them to call a professional that is local to the area they are going to be building this house, I have built a couple houses in that size range and I have installed hvac in more than a few of them, I can tell you people who build 10K sq foot homes, just hire the hi fi guy and write a check, they don't go to best buy...
do the math 10K sq foot hoomes average $315 a sq foot is over 3 million dollars!!!! These people hire guys to deal with this stuff, lol...