For starters have you increased with of field itself? Does that have any effect?
I'm also somewhat surprised because on my iPod, text size is automagically reduced for overlylong items (rather than the awful truncating you're getting)
However, I haven't tested with multiple field lists.
No, it has no effect unfortunately - see here. I would be OK with the drop-down list taking the whole page as the definitions aiding the user-selection are vital.
Any other ideas? I'm trying to use a portal concept now but it's a hassle as it doesn't "update" dynamically.