So, after amassing those 9950 (magic beans) you could build a fairy tale castle, then upgrade it to have it start working:
1 to 2: 40k stone, 40k pineplanks
2 to 3: 40k marble, 40k hardplanks
3 to 4: 40k coal, 15k steel bars
4 to 5: 3k map frags, 5k gold coins
After those near 2 weeks of upgrades you can buy some items using beanstalks made from more beans:
3x 5 Building Licence @ 1300 (beanstalks) each
3x Gold Tower @ 6300 (beanstalks) each
1x Major General - 10000 (beanstalks)
A total of 32800 beanstalks (less than 2 weeks of production time using x4 buffs (287.91 hours at 32sec walk distance))... After that (unless BB add more items to buy) the entire Fairy Tale Castle becomes absolutely useless.
So the only real reason to actually build the castle is to get the mere 500 (gems) reward from the quest line (gems plus a few minor items from quests related to building castle, some ewl, a valiant adv etc).
Economically it makes a lot more sense to politely ask a friend to borrow their castle for 2 weeks while they are not using it.
Your thoughts? Going to build one?
My current plan: I think I will try to borrow castle production time from a guildie (he's 10 days or so away from full upgrade) and get the Major General first (Got 9k beans now, so will easily have enough beans by that time). After that I might reconsider, though will likely just borrow time for everything... until such a time as BB add more items to buy with stalks.