I just went thru the same thinking a while back. The nice thing about TBH is that there is no right answer, so you need to build with the features you find important.
I ended up designing mine from ideas from multiple sights. The main hive I modeled after the slightly sloped plans this:http://bwrangler.madpage.com/bee/tmyt.htm
I like the idea of being able to wire a deep langstroth frame to the bottom onf the top bar. This way I just took a 5 frame nuc and moved it right in. As they build their own comb, I will slowly move back the langstroths and eventually remoce them.
I also wanted a working height that didn't require bending over and didn't want to deal with cement blocks, so I incorporated legs like here:http://home.comcast.net/%7Ebeekeeper23/TBH.htm
And finally, I didn't want to deal with heavy covers, so I opted for the metal one like here:http://home.att.net/~mcdonald/bees/hive/crowder/
FYI, I elected to forgo a SBB since it seems that feral colonies seem to prefer a closed environment and manage the temperature just fine. I don't like to use SBB year round, so adding one with the ability to close it off would just add more complexity to the build that I didn't think was worth it.
There is a wealth of options and knowledge out there on the web, just do your research and come up with what best fits your needs.