Continuing my quest for adsense friendly themes for wordpress, I have found a couple more suitable for simple modification.
I’m looking for something similar to the movable type theme used here.
Rampart would be ideal for ZX81kit
Zig-zag (similar to Squares) is easy to modify, put a link unit in the sidebar (maybe with a G! searchbox).
Tropical breeze could be modified in the same way, and would be good for a gardening site.
Tech-Bytes would be a good base for a theme if you had the inclination to modify the header image.