Moved here from the framebuiding forum.

I would look at the complete bikes for anything I was interested in and pick one that was built for flat bars. The main difference between drop bar and flat bar bikes is that flat bar bikes have longer top tubes. If a more upright position is what you are after, this might not matter much to you. Note that OEMs get much better prices on components than you will, so buying a complete bike is going to be cheaper. You might also look at hybrids, most of them will take wider tires.