Mine is getting a little wobble in it. I emailed RM about buying one from them but was told I had to go through my local reseller. I did see some on ebay though.
Its pretty easy so long as you have the correct BB tool to remove the retaining ring. Its a 16 notch for Shimano BBT-69.2/44mm centerlock. Got a cheap one from Amazon for $10.00.
As mentioned they are on eBay and many shops in the US and CA have them in stock if you goggle the PN.
Be aware there are two versions, one for Raceface and one for Sram, this is the chainring type.