I don't know how normal it is, but I have certainly seen that before. The big box stores carry all kinds of transition strips that should fit your needs.

Yes its quite common to see tile floors a bit higher then the surrounding floor levels. And yes there are several methods to blend this together. Sometimes its done with metal edge and sometimes with wood boards stained or painted to match the floor. We use marble saddles when we do this. It gives the tile a stop point that blends the tile to the wood.

When I do some tile installs.... Instead of 1/2" backer I will use 1/4" backer....this combined with normal full thickness 3/4" flooring results is a pretty even surface.

We changed flooring for several areas in our house, adding wood to tile, and tile to different type tile. I don't care for the traditional transition strips, so we used a decorative tile to make our own transitions. The decorate tile is typically thinner than tile/wood, and we were able to build up the thinset to make the transition flush with each type of flooring used. I wouldn't suggest this if the height difference is too severe, but for small differences in height, it works great ...»