EVERYONE that's gotten the HD SBP shiftkit has loved
it, usually swearing to never build another bike w/o it... heck - I've even got one, but I've not finished the bike it's on yet
Cruisers? Not to sound like a jerk but they're so common and can be so inexpensive new that I'm really surprised you tried ebay o_O Ya got any bike shops around you? Large department stores? Yardsales lol?