been looking at the adjunct project link from your article and it is very interesting. It's too bad that it doesn't break things down more effectively between full-time contract non-tenure (contingent) faculty and 'true' adjuncts who work semester to semester. That would be helpful in differentiating the oft-times large pay ranges.
Still, it's the most information in one place I've seen.
Chances of a union in my state (Nevada) is somewhere between slim and none. The only really powerful union here is the Culinary Union and they have never expressed any interest in folding higher ed into their mix.
One of the most annoying changes that the state has made recently is in regard to the number of courses we can teach. Technically, if we teach 12 credit hours in a semester we're eligible for benefits, so most of the departments make sure that we're never offered more than 9 hours. In the past, however, we were able to pick up a course or two at another institution (the college or uni in town, depending on where we're teaching) to supplement and because the pay came out of two different piles, the "12 hour" rule could be bypassed. We were also allowed to waive our right to benefits - which many did because an additional $2400 was worth more than the crappy health insurance they offer. Now, though, they have combined the 'databases', so we the '12 hour' rule applies regardless of location/s taught.
Meanwhile, it looks like the state is planning on switching to a performance based model for full-time faculty salaries and they're really looking hard at introducing MOOC's into the system, which will obviate the need for a very large percentage of the adjunct faculty - particularly at the college. We're all screwed, I guess.