Roland had a module - MBD1 (I think) that was a drum/bass module. Very many good bass sounds (from Fender slaps, to acoustic upright to phat analog. - and some decent drum sounds)
While no longer made, you may be able to find this module in the $150 - $200 range (maybe less).
The sounds of the MDB1 are also available as an add on sound card for the Roland JV & XP series keyboards.
Speaking of boards - I'm a big fan (as are many people) of
the Roland XP30. It comes with over 1,000 stock sounds, (many very good sounds) - with run for 2 added sound cards.
The XP30 has sound good bass sounds and good orchestra (even without adding sound cards).
Naturally, a sampler and a well selected sample library will likely give you better sounds - but that can get costly, and many sample disks can be very hit or miss.
