If the diac is used in the startup circuit, you might be able to use small bipolar transistors instead. Connect the emitter to the more positive side, the collector to the more negative side, and do not connect the base. 2 or 3 of those in series would get you pretty close to the 30v level. Not sure how many cycles it would work for but I have made a pulse generator using that principle and it has worked fine over a few hours at a repetition rate of about 80Hz, so it should last the life of the bulb given it's only used once every startup.