There's no such thing, don't let anyone fool you into thinking otherwise. All aircraft design and set up is a compromise. If you set it up to 3D well, it won't fly pattern well. If you set it up to fly pattern well, it won't 3D well.

That is an over generalization, but many many planes are decent at both. But if they excel in one or the other, then the other suffers.

Any pattern plane that is set up well will do SOME 3d. No it won't do every 3D trick in the book, but you can get it to hover, do harriers, rolling circles and the like. If you're looking for a plane that will 3D like crazy, then I'd suggest 2 different planes. If you can't afford 2 different planes, then you simply have to make a decision on what is more important to you. Which side of the pendulum do you want it to be better on?

If this is your first venture into aerobatics, then I would STRONGLY suggest a pattern plane and learn the basics first. You can always play with the throws and teh balance (to some extent) and get it to do some 3D, but it will be more work. If you get a pure 3D plane it won't fly precision worth a crap. One gust of wind and it's all over.

If you're referring to AA planes, all they are is a pattern plane that has enlarged control surfaces and massive throws. You can tone these down and they will fly pattern well, but keep in mind they are much more of a pattern plane than a 3D plane. Once you learn the basics and have a firm grasp of pattern, 3D becomes much easier. A lot of purist 3Ders are beginning to finally face this fact. And this is a good thing, there's room for everybody.

So, make your choice, and then decide what size range you're looking for. Genrally speaking, teh bigger it is, teh better it flies (but the more expensive it gets).

One more thought...what is too light? Planes that are built to crash don't fly well. Planes that are built to fly don't crash well. Keep that thought in mind. I used to build all of my planes to withstand a nuclear blast, but soon realized that the lighter they are, the better up to an extent. There are 3 areas that need to be beefy: the wing attach and spar, the firewall, and the gear attach. Everything else can be lightened because the load isn't nearly as high as one might think.

-Mike