Seems like having a 120 frame cold set and realigned to 130 makes a whole lot more sense for a whole lot less $...? Assume you're out in the sticks and your 120 cassette hub (or cassette) goes on the fritz, the lbs is probably just going to scratch their head for awhile as you call the Mrs for your ride of shame.
Then again, I'm usually missing something, what is it here?