Thank you for your replies. Abdussamad, that is kind of what I want but I think I prefer bip32. I'll look around a little bit more, it should be possible to do someting similar with sx, or other similar tool, but outputing a bip32 wallet instead.

Now, on a related topic, about the randomness of a randomness source, I am genuinely puzzled with some common advice I see. I might be missing something, but my biggest fear of loosing my coins comes exactly from RNGs. I do not trust them. We just need to look back a year or so to witness many "oh, the RNG was not so random after all", blockchain.info annd android bitcoin wallet have both proven to be weak on this particular matter.
I do not intend to criticize any of these services, quite the contrary, the fact that two well established wallets/services have been successfully targeted by RNG attacks goes to show that random number generation is indeed a weak link in the security chain. Therefore I feel much more peace of mind by controlling the source randomness myself.
I am not worried about replacing some randomness generated or collected by a piece of software on a machine called computer, what I am worried about is using that exact randomness. The reason being that it might not be so random.

btchris, I mean no sarcasm, irony whatsoever, but this confuses me:


If I type a long paragraph talking about a random topic on my mind, I can tell you with all  practical certainty that no other human being will come up with the exact same string, regardless of whatever method he uses to generate strings. I even believe 'banging on the keyboard for a while' could go a long way. In all seriousness, if the concern is reproducible patterns like "asdf"... then I think we're talking about people with very little understanding of large numbers, probabilities, etc. I think we can accept that a person can 'bang on the keyboard for a minute' and get a very random number as the outcome. Or, genuinely curious, why wouldn't this be true?