A couple of other options for high FG's:
1) If you keg and have an extra, go ahead and keg it, purge with CO2 and forget about it for a few months. You may find that it very slowly drops (I've had this happen on two occasions). That said, it probably won't drop a lot, which leads to #2:
2) Brew a really dry beer (you probably won't be able to do this with extract). Mash around 145-148, and let the mash sit for several hours. Use a high attenuating yeast. Then, blend the two beers together when the second beer is done fermenting. With a dry beer (1.005 is easily achievable) mixed with the high FG beer (1.030), you will land within a reasonable FG (1.017 or so).
I've had great success with #2 - you can even brew the same exact beer as the stuck one with a lower mash temp and save the first batch if you want the same style. Otherwise, experiment a bit and see what you end up with!