Yes the Wizzer tank is a good alternative as well.
A bit large at 1.2 gal (JMHO) but has a far better mounting system.
Unfortunately it wont fit on as many different frames as the CG kit tank due to the tunnel
I'm going to start a build on a Dorado Sherpa next.
Will be using a Honda Mini Trail 50 tank.
Should be a fun build. It will be a hunting bike for my Future sun in law...