Todd is right...a little research will show you a whole raft of kilt length jackets.

That having been said - and just asking for a discussion - you can get away with some jackets that are "conventional" ones but it depends very much on the cut of the jacket. Yes, it doesn't look quite right but if the situation calls for a jacket I think it's better to wear a jacket that looks a little (I stress little) off rather than show up without. The point seems to be finding jackets that don't look too long...and don't button up...and wearing a vest helps create enough of a visual seperation...and definitely wear the sporran. I've seen a couple of photos of Xsmarksers who've worn conventional jackets and they haven't looked too bad. A real kilt expert will take exception, of course, but, like I say, better to wear A jacket when appropriate. Blazers seem to be cut to look a bit shorter and the fronts are usually more open...I'd look in that department first.

But you will end up wanting a nice kilt jacket...they just look "right".

Best

AA