As someone already pointed out.....

1. Use the Band in A Box real track bass. There's a lot of options in that respect. And it sounds good and requires very little from you.

2. Use a midi keyboard with a nice VST to get custom parts

3. Do not use a guitar to try and do bass parts. The strings are not thick enough to give you the best quality sound. Trust me... I tried this and tuning down just gives a sloppy sound.

4. Ask someone who does have a bass and is willing, to lay down the track for you.

You can find my music at:
www.herbhartley.com
Add nothing that adds nothing to the music.
You can make excuses or you can make progress but not both.

The magic you are looking for is in the work you are avoiding.