Been looking under the seat - its pretty tight. There are 5 rubber bumpers on the seat bottom, 4 of them sit on the frame rails, the other sits on top of the battery.
Glider - on your suggestion - are you talking about the space between the oil tank and the plastic guard that sits between the tire and the oil tank? That looks promising. The EFI is mounted to a piece of plastic that is mounted in an opening in rear fender but the back side of it is open to the rear tire - I'd be afraid to mount anything there.
If that doesn't make sense I'll try to take a pic of the area.