im looking to sync playback to my iPad or MBP from my mac mini

I want to use my mac mini as a HTPC (using xbmx for exampe) and get exactly the same thing on my ipad or MBP (to view everything on the screen, and get audio as well (on both devices)). i have so far only managed to do it using splashtop on the ipad, and using audio midi setup to send to multiple channels (built-in and soundflower) which is a second or two out.

i want the playback synched so if im downstairs watching something on xbmc, my son can be in his bed watching the same thing, either on ipad on mbp.

also if possible, id like to do it to multiple devices which include: appleTV, ipad mini, iphone, another macbook, and even a galaxy tab 2 if its possible?