Engineer's Toolbox and Emasher Resource (formerly EmasherCore) are now out for Minecraft 1.6.2.
Emasher Resource has seen quite a few changes. The most obvious is that it now adds ores, gems, and metals, and the terrain blocks and hemp have been moved to it from AS#B. All world gen can be customized and disabled, and all but hemp and algae now have retro-gen.
Engineer's Toolbox hasn't changed a whole lot from the last 1.5.2 version. It now has the spray paint and hand boiler from GasCraft in it, and all the known bugs are fixed. Unfortunately, dismantled sockets no longer have the shimmering effect, and you can no longer control the EU output voltage (due to IC^2 API changes).
The developer API is still coming. I meant to have it out ages ago and for 1.5.2, but until about a week ago, I've been really busy IRL, and just haven't had the time. Once I get defense and GasCraft updated, I'll finish off the API and release it.