Ok I have 1 Backplane left and I will send you a PM on that.
As for the PSU you have 2 sources for them. Overtek LTD and KDM Power. I have been exchanging email with KDM Power and they now have a newer Direct Replacement PSU with a longer power cable that is correctly wired for the MSS so there is no longer a need for their adapter cable. They have also informed me that they would sell adapter cables as a separate item which will allow you to connect a standard PSU to the MSS for PSU Testing to allow you to rule out if the issue is the PSU or related to other issues other then the PSU.
Both KDM Power and Overtek LTD sell their PSU's on eBay but before you opt to purchase a KDM PSU send them an email asking them if the PSU they are selling is the newer one with the longer power cable or the older which requires the adapter cable. Anyway these are the only 2 suppliers of PSU's that are confirmed to work with all MSS Models.
As for the fans they are 80mm PWM or Pulse Width Modulation and are mounted in the MSS on Silicon Mounts. You can read about them on the following link:
http://www.formfactors.org/developer%5C ... Public.pdf. I have only had 1 fan failure in an EX470 since 2008 but because I repurposed 2 MSS units to become Port Multipliers it provided me with extra MSS Backplanes and fans.
The one issue with fans you have to be careful with is the CFM Rating which is the measurement of how much air flow they can generate if you spec vs the db level with is the measurement of noise. Most people like their servers to run quietly because they are often in locations where noise is a big factor so if you buy a fan because of its noise level but do not pay attention to the CFM Rating you may not effectively be cooling your servers components and with the MSS relying on a passive cooling this is critical. HP Opted to use PWM fans because they could regulate the speed the fans were operating at based on temperature conditions within the server so if the servers components are cool the fans slow down and reduce the noise level but if things heat up the fans spin up and which raises the noise level.
There is also another thing to keep in mind about air flow keeping things cool and that is if the environment your in is on the dusty side it would require you to clean the server more frequently because the higher the air flow the more dust it will bring into the server and then the dust build up acts like an insulator causing more heat so its important to keep all these things in mind when it comes to selecting newer fans.
For the EX470 Alex wrote a very nice ADD-IN called MSS FAN CONTROL
http://www.mediasmartserver.net/add-ins/#MSSFanControl this ADD-IN allows you to change the way the fans operate in your EX470. I opt to run my fans at full speed because I have upgraded the processors to either BE2300 or ADD3800+ CPU's and keeping those processors cool is of importance to me and without this ADD-IN I would not be able to keep my servers running because they would just shut down when the Processor Temps were elevated.