(Perhaps someone should export honest and competent civil servants and politicians. Perhaps the Swiss can be coaxed to spare some? Italy would certainly benefit from an influx, too.)
A recent example was one of Nigeria's previous ministers of finance who was paid by the UN to move back from the US. Nigerian ministers were at the time paid only ca $6000/year - no wonder corruption is high in many of these countries when these same people often could make hundreds of thousands, or millions, in the private sector.
See: http://en.wikipedia.org/wiki/Ngozi_Okonjo-Iweala
In her case it didn't go down to well with the other ministers, and that's likely a problem. A solution might be to set up a fund to provide better salaries in return for the government agreeing to regular independent audits of ministers finances and publishing the findings (... we saw how much fun that could be even in a country like the UK).
Of course many governments would decline, but some at least seem to want to clean house. It's a lot easier to clean house if the financial situation doesn't provide ridiculous levels of temptation on a daily basis.
They'd probably just be imprisoned/killed by the corrupt incumbents. You'd have to replace the whole power structure at once, and back it with force of arms - which kind of brings us back to colonialism.
I was referring to the influence both have on not considering Africans as people who can handle themselves. It will take time, trial and error, but those can't be avoided.