Thanks!
Thanks for all your replies so far. It sounds as if contacting the US Hurricane Hunters is probably the best way to try to get myself and cameraman up into a storm. The descriptions are wonderful, so thank you for everyone who has posted or contacted me so far. It really helps us plan if we know roughly what to expect - and if we've only got a few minutes to film then planning's vital!
False Capture - thanks for your description. Sounds like you're in a particularly good place to see it (maybe we'll head to Africa - it is a lightning hotspot apparently). Can you give me any indications of roughly how frequently electrical storms give good displays, or hints as to how to tell if one will? Is it pretty much a case of 'fly into one and you'll see it', or is it much rarer than that?
Thanks again everyone - I hope we can capture this phenomenon safely on camera to let everyone enjoy it from their sofas!
Alex