i am just wondering if you can play a guitar through a guitar amp and run straight into a bass cabinet
Im not an expert in this department, but im pretty sure the speakers in the bass cab won't be able to play the much higher pitches of the electric. And even if it can, it could quite easily damage the cab.
You can do it if you really have to, I think the whole controversy about it is a bit mythical/misleading. Kind of a urban legend kind of thing. I know that the low frequency of a bass wouldn't be good for a guitar amp, but I'm pretty sure it wouldn't kill it without extended use. As for guitar in bass speakers.. I think that would be fine, just use them respectively. Oh, and are you using a guitar head for the bass cabinet or are you using a bass head as well?
It'll be fine. Some people prefer bass cabs for the bassier sound.