Are you sure you're not talking about an 8000-series scope, rather than a 6000-series one? My MSO6054A was about $8500 on eBay, new in box but about half normal retail, and Agilent was running a special where they'd enable the maximum memory (8M points, which is actually just a software option) for free.
There's definitely no way to get 256M points on this particular scope, or to pay $100,000 for one.
But yeah, firmware support from Agilent has been outstanding. The DSO/MSO6000 line is rather 'mature' at this point, and they have released updates that enable a lot of features for free (8M, waveform statistics, RS-232 lister, and tracking cursors).