Currently, there are very limited coil spring shocks available in 165mm eye-to-eye and 38mm travel, but there used to be plenty. The only coil shocks that I am aware of in 165mm (6.5") that are readily availble are:
No longer produced coil shocks in 165mm x 38mm:
- Noleen made a great shock in that length that came on Giant ATX 990's;
- Fox also made its Vanilla R and RC models;
- Manitou Metel 2006 (and maybe earlier);
- Marzocchi Roco F
What sort of weight could you expect?
A coil shock is not going to be as light as a air shock. Air shocks like the Fox RP23 in 165mm i2i weigh around 208g. The body only of a Fox Vanilla R weighs 175g. A steel spring weighs around 325g in that length, so total weight for a Fox Vanilla R in 165mm with steel spring is 500g. A titanium spring is about half the weight of a steel spring, so a Fox Vanilla R in 165mm with titanium spring could come in around 335g.