If raising the pickup action doesn't help things, try using a compression/sustainer.
There's tons of them out there. Boss for instance makes a single pedal or you can buy a multi-effects pedal with one in it.
You can set it up so that either does just a little or a whole lot of sustaining.
Basically what it does is smooth out the notes overall, and while the note is starting to die out, it gradually raises the volume.
If you have High Bandwidth, there's a video here showing how it works and sounds like.

http://www.guitartricks.com/lesson.php?input=9478