First of all, the Schecter Demon 7 (lefty) guitar is a quite reasonable priced stock guitar that comes with a good value for the buck. Therefore I decided that I could just go with some more radical modifications which I never dared to try before.
The functional modifications: Just like with my Jackson, I rewired the tone pot to work as a high-pass filter: I removed the tone pot from the circuit, removed the capacitor; then added a 1 uF capacitor after the tone pot to the signal line and then after soldered the tone pot in series with a 280 (?) Ohms resistor to the ground.
Furthermore, I replaced the 7th string tuner with a Kluson bass tuner in order to be able to put a real thick bass string there.
For the non-functional part: I used a Dremel tool to carve in some bifurcation lines that flow from the tip of the head towards the bridge. I also painted the line-parts on the fret board and on the pickups in a yellow-greenish color.