I’m looking at a similar sort of frame (not for 15ft drops tho, 5-6ft max) i looked at the Cove Gspot but the rear air shock put me off a bit, i’m debating an Ellesworth Moment 6 inch travel can be built up to just over 30lbs or a lot more robust, i had go on my mates at Inners in the summer, it climbs really well and was excellent on the descents, they have some good offers on frame and fork combinations at the moment at Freeborn.
My other mate has just got an Intense Slope Style, ridding position is spot on you really sit into the bike and not perched on top, the only thing you can’t fit a front mech so a little limited with the gears
Cheers
Nick