DonMaico ... My local branch of MVC (Camberley) has a selection of DVD-A & SACD if you are a millionaire you could buy from them
For us non-millionaire types I have started using dvdpacific.com who are based in Miami & DVD-A & SACD stuff is about £9 - £11 depending on which postage you go for (airmail is quicker - 4/5days - surfacemail is slower 7/10days but cheaper!)
cduniverse.com have a big selection too at similar prices but I havent used them yet ... HTH ... Paul
You can play dvd-audio discs in any dvd player as most of them contain a dolby digital or dts soundtrack. But to get the high resolution sound off the disc, you must have a dvd-audio player connected to an amp that has 6 analogue channel inputs.