I thought I would give it a try with my old DeathAdder. (has a crack on the left finger)
First I took it apart and removed the palm rest. Grabbed a roll of masking tape and a sanding block I had...
Turns out the plastic on the palm of the DeathAdder is clear. =D
So I sanded it down where I wanted the TL logo to go.
I printed a small TL logo and cut it out on some masking tape to make my stencil.
Added some black spray paint and peeled the tape off. Lines are not as crisp as I would like but still looks good.
Last picture in the dark. Let me know what you think =D