I have a hollywood plus. You can't put a general signal out through it no.
Any file format that DVD station will play can be output, but not general graphics. Since you are using a passthrough cable anyways I really don't think it would be that hard for them to do it...but hey what do I know? Anyways DVD station will play Avi's, Mpegs, VCDs, DVDs...that's about it.
Just a note on TV-out, the Hollywood plus has excellent TV-out quality much better than the brooktree chip (featured on my roommates V3-3000 and most (but not all) nVidia based boards with TV-out). The ATi Rage Theatre chip (Radeon Vivo, AIW) is an excellent TV-out chip though, nearly as good as the H+, and the Radeon has hardware DVD assist. Less than 10% CPU usage playing DVDs on my older 550 Athlon...
I think you should consider a Radeon as well (either the AIW or the Vivo) excellent 2D and 3D quality, very fast 3D and excellent DVD features. I'd ditch my Voodoo3+Hollywood Plus for a Radeon Vivo in a second, but I'm a little broke ATM...