i'd stay away from a water feature on your first build. they can be major headaches. what kind of filter did you plan to put in the corner? you would have to lay the repticlear on it's side, otherwise, it stands 9" or so. here's the problem, only you know what you want your tank to look like, so until you have some sort of structure built, i can only give you general ideas. the easy way out would be to get one of those rock waterfalls that holds the filter in it and utilize it flowing into your pond area. don't get me wrong, there is nothing wrong with going the easy route on your first build.

did you read over my mantella tank build yet? i think alot of your questions may be answered in it. i wrote it as a step by step detailed tutorial. and it incorporates a lot of the features it sound like you are looking for. i normally don't direct people to my build threads, but i think in this case, it might be helpful