If you are wanting to stick with a large 2-stroke glow engine, and think the 1.60FX is less than what you want - try a Moki or Mark 2.10 - chiefaircraft.com or morrishobbies.com carry them. The Marks are the same basic engines, rebadged for US distribution from what I have heard.

To the Saito 1.80 you have - it would be a decent candidate - and I've seen smoke on one and it looked fine - you need to create a pre-hearter coil in the muffler before it dumps out to let the smoke oil heat up good.

www.rcdon.com has a good how-to on this process - click on Aircraft Videos then on supersmokers part 1 and then 2.