I learned a way of doing a round house off of some Kyokushin videos that were posted on here a while back.
From a conventional stance and your partner standing at 12 O'clock, you chamber your rear leg at 3 O'clock while starting the pivot like normal. You end up maxing out the power earlier in the arc while getting your leg up higher, earlier, so that you can throw a snap shin kick from inside punching distance without piking.
For MMA sparring, it simultaneously feels dangerous for me (getting bowled over or thrown) and dangerous for them (ducking their own head into a very strong shin kick) which makes me wary of using it, but I have a few times and it feels good to hit with.