No. As of already it is not possible, unless you got an Ipad 2 with SHSH blobs saved for 5.1.1.
Mickey330 said:To add to this - that iPad2 also has to have the SHSH blobs for any version of iOS 4; the iPad2 can't be downgraded without both sets.
it's been this way since iOS 5 was first released (and Apple changed the way the APTickets worked). As a general rule, once you've upgraded and Apple closes the signing window, there is no going back.
Marilyn