ok so you know what your doing at least , id still reommend bining the bose sub for a small proper one though.
there are plenty of units that will do everything i one bar card slots but tbh your best with an ipod or as harddrive, hardrive being the cheatest and saves mesing about wiht itune sand video on the ipod.
pioneer seem to be the best all in ones out there , kenwood do some i dont think theyre higher end units have sat nav so youd need the add on , with your budget id be tempted by the alpines , they will need add ons for both B and nav but the i tihnk the new nav add in also add BT and unlike others physically slots inot the front of the HU !
http://www.caraudiodirect.co.uk/alpine-iva-w505r.html
wihtn this
http://www.caraudiodirect.co.uk/alpine- ... kbird.html
will do nav ,usb , ipod , BT .