E550 seems a little much. They are very hard to find, but I don't know if I could justify that price point. I bought my G Rudolf Uebel, Reform-Boehm, for about $220. Granted, the bridge key is broken but that's a sub-$100 fix, placing it in the $350 maximum range.
I don't know much about these. I do know that they are pretty rare (at least in the US), and considered to be pretty good.
For your purposes, I doubt you could spend the $200 on a refurbishment (making it E750), and then still be able to sell for a profit. They're nice, but not THAT nice.