After having left him alone for a number of weeks, I decided that my librarian was done, so went ahead and based/sealed him.
I also did up some more terrain. I picked these up at a consignment sale, along with some radar dish/blaster things and some misc other toys for my son in a bag for $2.50. They were originally some kind of Star Wars Hoth set I believe, but I sprayed them and repainted the cables to turn it into a desert/earth emplacement.
They split off, but can join together.
It's a decent size for 40K; here's the librarian peeking over, able to fire but still get his cover save.
Since these things are pretty sturdy, they may end up on loan over at Gaming Underground.
Don't overlook yard sales, church consignment sales, thrift shops and the like! Some real bargains to be found sometimes.