Star quad was a bit bulky for my tastes, I recabled my Grados with them and I didnt like how heavy the cable was. If youd like to use star quad, you should check out the Cardas cables, which is a more flexible and lighter shielded sterquad cable.
If you consider how much wire goes into a senn cable, that would also be a good reason why the senn cables are so expensive. When I build a 7' cable I end up using 28 feet of wire. 28 feet of wire is very expensive, compared to an 8" cable that uses 2.5'.