I too like the Lee Spears hammers...if only I didn't ruin the pads on all six sets I have I have to learn not to play SO Enthusiatically!! I have both the "Ebony" hammers which are a bit heavier, but resonate beautifully, and well as his lighter and softer "Blond" hammers. I have written to Lee about obtaining more leather to glue back onto these poor abused hammers.
I have also dipped hammers in "tool handle rubber" , a liquid yellow or red rubber compound used to cover tool grips, Quite an unusual sound, very muted..and dampens the sustain a bit too. I did this with the set I got with my Folkcraft 15/16.
The aluminum hammers I got from Donna Missigman near Pittsburgh Pennsylvania are fabulous for ragtime...
Lastly our mentor Paul Van Arsdale used to use Hacksaw Blades filed down as hammers...I wonder how they sounded ?