If you have Guitar Pro, then you can use GP files and turn the Bass track down or even right off... Just because it's called Guitar Pro doesn't mean it's only for Guitar noodlers...
if you haven't got Guitar Pro then use TuxGuitar instead... it's cross platform, open source, completely free, and opens/saves guitar pro files, so you can open a .gp5 file, edit the bass volume right down and then save it off ready for loading back up.
You can also export out as a midi file with the new volumes and use a midi player with good instruments to play it with and capture the output as an mp3 file.
Unfortunately, a heck of a lot of Guitar Pro files are, to put it mildly, cr@p. You have to look hard to find good ones or else create your own.
If you can track down some good midi files, then TuxGuitar can import them for you so you can edit the Bass track out or down.
TuxGuitar can be found here:
http://www.tuxguitar.com.ar/
ps, you can also use it to print out the Bass part in normal sheet, tab or combined sheet/tab form. And you get a funky fretbvoard mode which lets you see the notes as they're being played or input your own for creating your own music.
here's a midi to mp3 converter that's freeware... most of the others are payware/shareware
http://www.brothersoft.com/mp3_audio...eow_42945.html
don't know how well it works as I don't use windows, I use Timidity on Linux to play my midi files piped through oggenc to make ogg files.
