Thanks mariano for the history :) This is the vision we have and that is presented in the vision file available in the consortium web page on the pharo-project.org :)
Hi Denis. I want to say a couple of things about this. First, you are not the only one wanting this. In fact, that scenario is one of the reasons we are investing a lot of time in the infrastructure:
1) Pavel Krivanek has been working a lot in making the image more modular, being able to cleanly unload and reload packages. This was the first step. 2) Jannik Laval continue that effort trying to remove lots of cyclic dependencies between packages. 3) Guillermo Polito started to work in the bootstrap. He is now able to bootstrap images from scratch (contrary to Pavel's PharoKernel where he was unloading packages). 4) Esteban Lorenzano is working on a new ConfigurationOfPharo that will let you take a kernel/bootstraped/minimal image and load just the packages you want. 5) Camilo Bruni, Martin Dias, Guillermo Polito, and Toon Verwaest have been working in a new class builder based on layouts. The "old ClassBuilder" is really difficult to maintain, understand, fix, etc. When you load packages, the class builder takes an important role. Therefore, they were working in a new class builder, which, from my point of view, is way better, object-oriented, tested, etc. 6) Martin Dias and Me were working in Tanker, a tool to export/import packages of code using Fuel without Compiler.
So.....as you can see there is/was a lot of work going on related to what you need :) It is not 100% ready, but we are getting there.
Cheers,