ill my ipod touch is jailbroken with redsn0w. later today ill try to copy the blackra1n app from my iphone, and try to put it on my ipod. if it works then it does work 100%, if not, whatever. you already gave him his answer, i just posted what i was gonna say before i saw your post.
Junk, I admire your creative thinking, but I got a feeling it ain't that simple. If it is, I'll drink a peppermint tea, maybe even a beer, in your honor.
On reflection, BR definitely depends on an iPhone being JB'en -- have found that out repeatedly. Seems like a stretch to assume that simply copying a file into the device would circumvent or actually perform the jailbreaking process. Just thinkin'.
If that imaginative technique DOES somehow work out for you, could you send me the blackra1n ipi (or whatever) file? I could give you my e-mail in a pm. 3.1.3 destroyed my BR, and I don't know anyone else here in Japan using it. Anyway, plan to play with Explorer this weekend.
Good luck!