Used Les Crowder's design with the ends influenced by Michael Bush's. One observation I have about Les Crowder's design is that the hive is pretty darn shallow (mine are only about 7" deep). I don't know if that's going to be an issue in the sense that there might not be enough room for them, I suppose I'll find out. But that design seems to be pretty widely used so it must be OK.
For the top bars we used two 2x10x10. Then ripped three 1.25" and three 1.5" bars from each board down the entire length (this leaves a 0.25" spacer when you rip the final length). Then we ripped the angle in each side, cut each piece in 20" sections, then cut "up" from each end about 2". Then cut the bevel towards the outside. They turned out pretty darn well. About the only thing I would change would be a little steeper angle for the bevel. The method is outlined here in post #50 by stdavis: http://www.beesource.com/forums/sho...to-build-cheap-top-bars&p=1047726#post1047726
Each 10' 2x10x10 cut into 18 1.25" bars and 18 1.5" bars perfectly, in addition to yielding plenty of 0.25" spacers if we need them. Total for the bars was under $20 in wood. The hives are 48" inside and hold about 34-35 bars with a gap in one end for the top entrance.
The last thing we did was cut in the observation windows and put on covers for the windows. Unfortunately, we had an "opps" and forgot to do them before we assembled the hive. Not a huge deal, but it did make their install a bit more difficult.