Harbor Freight has a 'ratcheting crimping tool' that might do the trick, but I don't know:
http://www.harborfreight.com/ratchet...ool-97420.html
For sure, if Harbor Freight carries such a thing you can get a better one if you're willing to spend more money elsewhere. Just bring a couple rounded off spoke nipples when you go looking at them, to make sure the dies are the right size. As for soldering, lots of people have posted on this forum that they successfully soldered stuff to galvanized cable; you may have similarly good luck. All I know is, I tried and failed.
Rhm, if you're ever in the mood, could you post a photo or two of your crimping tool, and a photo of what the spoke head looks like after crimping? Brass spokes heads seem pretty robust to me--I'd imagine that a crimping tool would have to deliver substantial leverage to deform them as required. The Harbor Freight tool seems kind of light-duty to me, but that may be because I don't really understand what's involved. My optimistic plan at this point is to solder if I can but crimp if I must.