Thanks for the replies everyone. I thought about going to the tail wheel but in cruise that would an uphill slope or close to it. Also, more potential for freezing.

I thought about a tube going down the gear leg. Also icing issues.

I have done the Gatorade bottles and johnnys before and I want to get away from this as I can pee up to 5 times on a 5 hour leg of I'm staying hydrated. If I have to stop ever hour and a half it makes my average speed well below my cruise speed.

If I can stay airborne for 5 hours, then I could be just as fast on average as something that goes 140kts who stops to pee once on the trip.

I just want a simple system that when you are done you can flush with a bit of water and there is no smell. I think the simpist way to this is as I mentioned before, some how using the exhaust to keep it from freezing and having it as far below the fuselage as possible. The hot air may instantly vaporize it as well.