I really wish that someone had taken over production of the Cox reed valve engine now that the current mfg has apparantly dumped them - there are a lot of models that are designed around the concept of a compact engine with integral fuel tang, and the spring starter on the Cox engine is a big help too, especially for beginners. However, I have a Brodak .049 (Mk. I) and though it doesn't have the integral fuel tank, I think it's a good alternative to the Cox .049's. It's readily available, reasonably priced, one big advantage is that it takes regular glow plugs instead of expensive glow heads.
cheers,
Ken