Here's one found using a Google search that mounts to the trunk lip (probably why it's called a trunk lip mount). You loosen the two set screws on the mount. Slide it onto your trunk and tighten the set screws to hold it secure. This provides a standard NMO mount for your antenna so many standard antennas can be used as desired. Just make sure you have good clearance so the mount doesn't rub against the car when opening and shutting the trunk.
NMO-TLP [LAR-NMOTLP] - $40.00 : Radioworld
Larsen also makes an "L Bracket" mount (TMB-34 [LAR-TMB34] - $7.00 : Radioworld
) that you screw into your car's quarterpanel in the trunk or hood area and install a standard NMO mount into the bracket. You can then use any standard NMO mount antenna on this as well.
Either solution works rather well and which you use would depend on your particular situation. The L-Bracket does require some small screw holes while the Trunk Lip mount requires no holes, but generally there's some minor paint damage from the set screws. The damage from both types are minor and easy to touch up.