Location of skeleton spawner, on Utopia, approx 600 blocks from the spawn. Price: 6000 rupees. Offers will be considered. It is totally untouched, except I left a couple of torches and a hole to the surface. I even left the mossy-cobble and 2 chests containing iron, saddle, bucket, cocoa, gunpowder, etc. You can have all that too! It's very easy to get to. There is nothing around it; no evidence that anyone has been there. I was wandering around dark caves when I found it. It's on the Utopia server, so more efficient. (Note, although only Supporters can have a residence on Utopia, anyone can go there). Skeleton spawner 'grinding' give bones, bows, and "Power-I" bows, and are quite easy to make. I can give you the coordinates, or take you to it. Disclaimer: http://empireminecraft.com/threads/guide-selling-mob-spawner-locations.9738/ Please contact me to buy (PM, or message through the website).
=== Selling it to Charlie568 === I'll sort out details via PM's. If it doesn't work out, I'll re-present it here. Thanks all.
No, it's a fresh spawner, untouched, that I found. And it's 600 blocks out. You made me a dual-grinder, about 4000 out.