I worked in a computer shop for a year, the biggest issue with LCD's I saw was the inverter going out. I can only recall one case where the backlighting went and only a few where the PSU went bad. That's also just excluding cracked screens from drops etc. I personally have yet to have an LCD fail, I had a used LCD TV that had overheating issues but that's about it.
I don't see a group-buy being feasible. And you wouldn't save all that much compared to just buying a single monitor. They retail about $260 in Korea. On top of whatever other fees, the guys selling them for $375 aren't making much after paypal and ebay fees, and shipping it express.
LCD panels are backlit with either LED or CFL. The inverter generates the ~700-1200 V for the CFL from a lower voltage power source provided by the motherboard. This can either be integrated into the logic display connector, or it can be a separate (usually 4 pin) connector that plugs in to the motherboard. In practise, the physical CFL tubes or other fails internally in the panel more often than the inverter, if there is a separate board for it (which is uncommon, but is prevalent in the white and black Macbook 13"). There is a similar "driver" board for LED-backlit panels, but this is also commonly integrated on to the back of the panel in laptops. One notable exception is the Lenovo X220 tablet, which has a separate board driving the LED's. They refer to it as "LED board" in their service manual.
I've only worked for 8 months, but I've seen several backlights go out in computers with separate inverters, but as I said, most inverters are integrated to the panel, and LED drivers are almost always not a separate part.
Computer internal power supplies do go bad, though AC adapters are much more common. Usually if one of the Voltage regulators on the Motherboard that drops the DC from 19V (fujitsu, some gateway, toshiba) or 20V (Lenovo) to 5V or 3.3V then it'll take out enough of the rest of the motherboard, that it'll need to be replaced entirely.
As far as panels failing, it's often from spills, drops, etc. I have seen them go, but usually an entire shift register will drop out, resulting in one or more white bars across the display. It's pretty frequent for me to see this: We get at least one per week. In fact, I just replaced one in a HP ("Compaq") 6710b where the back lighting was perfect, and the panel was broken. Lucky for me, HP ships the entire assembly.
Also, I would say that the cables failing is also relatively common. I have done more than one Apple macbook white where the panel and backlight are great, but the cables have some break internally.
Finally: Not all panels are reliable: The Lenovo X220 tablet and laptop have already gone over 3% for non-damaged screen issues. (We started selling them in the fall.)
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As far as GB's go, I thought it would make financial sense to run one, but if that's not really the case, then perhaps I'll just get one or two of these from ebay. Are they energy-star? If so, I can get 50% off through my work's efficiency initiative.
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I got to see a new Apple cinema display we replaced the "logic board" in. It looked nice, but it wasn't as amazing as everyone says IPS is. Unless of course the "mid 2011" didn't have an IPS panel. Humorously, Apple's parts-ordering system "GSX" told us to back up the hard-drive before replacing the logic board in the Apple Cinema Display.
