I suck at project estimation
But based even on our preliminary SWAG on the client's needs, and a look at the horrible system we're going to replace, I have such a hard time guessing how much time it will take to build. With solid requirements, my feeling is that it shouldn't take more than six weeks. All of the hard work will be done in the requirements and design process.
As kind of aside, what do y'all use for requirements tracking, and does it have some kind of bug tracking capability as well?