I heard about this problems too. I bought third party caddy from ebay for 13$ and it suits well.
In my previous post i was asking, if the HDD in caddy is not affecting battery life (even if it is not spinning). It has to be powered even if not spinning/being idle or standby or whatever state it is.
______________________________________________________________________________________________ T420 i7-2620M, 8GB RAM, NVS 4200M 1GB, OCZ Agility 3 SSD 120 GB + 500 GB HDD in Ultrabay, Windows 7 Pro (64bit)