I just picked up a 4mm driver set from a local surplus hardware store for $9. Nice telescopic bit driver with a snake extender and about 40 bits in all shapes and sizes including the tiniest torx I've ever seen, a good selection of hex, and even the mostly useless pozidrive in 2 sizes.

Now I just have to magnetize the bits somehow so they'll stick in. The fit is good so they shouldn't need much.