Aero helmets for long heads?

I would really like to find an aero helmet that fits my head, but no luck so far. I have tried everything I can get my hands on locally (Giro Advantage 2, LG Rocket, LG Prologue, Limar Crono, Spiuk) and of them the LG Rocket is the closest, but is far from a “good” fit. My problem is that my head is more oblong than round and a helmet that is large enough to keep from squeezing my head front to back and giving me a terrible headache after 20 or 30 minutes is so wide that I can almost put my closed fists on either side and it wobbles like crazy. I tried dozens of road helmets before I settled on a Bell Alchera (best fit I have found, but not “like a glove”). I would like to try the Bell Meteor just to see if their shape is consistent, but as it is not certified in the US I cannot find one to try (and would be hesitant to spend that money on a helmet that I could not race even if it was a great fit - even though I would like to know if it would fit). Does anyone else have any experience looking for helmets that are more long and thin than round?