Version 0.2.7 Beta 1 of the Namecoin Lightweight SPV Lookup Client has had its source code released. Build instructions are here (it’s the “bleeding-edge branch”). Binaries will be made available later. Meanwhile, the former bleeding-edge branch (the branch that introduced leveldbtxcache mode) has graduated to partially-stable. The former partially-stable branch has been deprecated.
Happily, the 0.2.7 Beta 1 release is using an unmodified upstream libdohj, since Ross Nicoll from Dogecoin has merged all of my changes. I’m still working to get the relevant ConsensusJ (formerly bitcoinj-addons) code merged upstream. As usual, the SPV client is experimental. Namecoin Core is still substantially more secure against most threat models.