I just did as Dirk said and pledged 2x120€ + 1x shipping for two coloured KBDs (now signature too)... The way I see it that if you were an early bird at the beginning, then your early bird 'advantage' will be available in case of addons(=extra TOHKBDs) too, whenever you choose to use it, if you choose to use it. For example if I would've pledged 100€ for the "SUPERMEGA-earlybird" reward of 1 standard TOHKBD, in that case I could have just doubled that now (2x100€ + 1x shipping) and get two coloured TOHKBDs! I may of course be wrong though.