I have absolutely no idea about how the FubarII or III sounds like. However, from all the posts that I have sifted through in the past, it seems like the Zero DAC is one of the best "bang for buck" DACs around, since it is easily mod-able, comes with its own headphone amp, and provides a pretty decent sound.
As for the cables, I do not think that you'll need a specific RCA to 3.5mm wire. Instead, what I'd recommend is to simple purchase a pair of RCA cables from LHS Electronics@SLT and then simply buy an RCA to 3.5mm adaptor that you can find easily in any electronics stores.