Lynskey Pro 29 (frame) is a titanium hardtail designed for trail riding/xc racing. In great condition, ready for geared or single speed build (sliding rear dropouts), and has 18.5 in seat tube, which was slightly too small for me. I am riding the same frame now in an XL.

Frame only: $700
Also available:
Lynskey Ti seatpost: $100
Rock Shox Reba (80mm): $75