Yep
1st instance:
When my G5 2.5 had a liquid cooling leak the cost of the repairs exceeded the cost of the machine new (I think I was quoted $3100 for the cost of the repairs plus parts) as it took out the power supply, processors, liquid cooling unit, cooling unit fascia, pretty much everything was swapped out internally except the case, the superdrive and hard drive. That repair saved my bacon as there's no way I could have afforded that.
2nd:
My iMac Corei7. Just tonight it was found that the internal drive failed so they're swapping that.