Most of the projections we've seen for 2013's biggest solar markets (Solarbuzz, IHS iSuppli, Deutsche Bank) put Japan as #4 behind China, the US, and Germany, and ahead of a number of countries led by Italy. Maxim Group and Lux Research have Japan squeaking into third place. But now, one analyst sees Japan's solar market surging in 2013 to an eye-popping 5 GW -- raising questions whether the nation, like others before it (think Spain) is overheating.