Update: Biotinkering, laws and regulations
Benjamin commented on the post "DIYBio and biotinkering - Laws and regulations in Germany":
Since writing the original post, I've learned that this is not completely true. You can do some genetic engineering even without a BSL 1 license - namely, "self-cloning". The legal text is a bit mushy on the subject, but essentially, you can genetically engineer known-to-be-safe organisms if you use only sequences that are naturally found in this organism, or one that is "phylogenetically close", provided you don't release the result into the environment.The legal issues are pretty simple actually - you just cannot do any genetic engineering (including bacterial transformation) in your garage. Simple as that. Sorry.
I've talked it over with the office that is responsible for granting BSL licenses, and they suggested it may be OK for a biotinkerer to, for example, modify E. coli K12 with elements found in E. coli. The University Reading offers a kit, "The Transformer Protocol", which implements just that. It's aimed at teachers, students, and other experimenters who don't have access to a BSL 1 lab but want to learn about the basic procedures of bacterial transformation. The fine people of MadLab in Manchester have actually used this kit in one of their workshops recently.
Conceivably, it would also be within the bounds of this "self-cloning" provision to rearrange (inducible) E. coli promoters and E. coli genes to get externally inducible expression of some gene of interest - not exactly ground-breaking science, but probably fun, and a good way to get one's feet wet.
I think it would also be possible here to rearrange/recombine traits of different, say, apple cultivars (provided, of course, that you know which genes are associated with these traits, but that's a different problem). I'd want to talk this over with said office before I actually try it, though - better safe than sorry.