I did a bit of FEA in my engineering degree, using ANSYS- but it was mighty complex. I think you are taking on a huge project here!
There is decent FEA software around, and perhaps it would be better to develop a plugin that would communicate between SU and FEA, rather than trying to do stuff from scratch? I was for a start, really impressed with an application called GMSH, but it may be too complex for architects- more for engineers, but at least SU could be used as the CAD modeller for GMSH? Perhaps the physicists (you need these guys, more than mathematicians!) at GMSH could also help with basic physics problems.
For further reading, I'd recommend "Structural Timber Design" by Abdy Kermani, published by Blackwell Science Ltd (available from all RIBA bookshops ISBN: 0-632-05091-8). This book covers all the properties of timber, and their types, as well as the complex formulae needed to solve various problems- like how strong timber frame walls should be, to withstand wind pressures from various sides, and the calculations needed to have just the right amount of wood, to withstand those pressures, at the most value for money (sustainable technology), and the all the maths needed to work it all out. It's not a 'cheap' book, but it's all in there, and best of all, to British Standards (BS 5268: Pt2: 1996). There is also a bit of info in there, on the software called MathCAD.