So I have a Blaze Spawner in the Nether, and am paying AlexChance around 10k to build me a trap for it. I am selling the Blaze Trap for 20k rupees, which you will easily make back if you use the grinder and sell enchanted pickaxes. The grinder is on SMP9 if that affects your decision. NOTE: I have my own spawner nearby, if you grief ANY of it, I will hunt. You. Down. Thanks! DISCLAIMER: http://empireminecraft.com/threads/guide-selling-mob-spawner-locations.9738/
Unfortunately rob, it is not. However, the entire stronghold is yours to explore. For example, mine has 2 spawners within 40 blocks.