MFOS has a very interesting and somewhat complicated guitar synth project available -

The SUB-COMMANDER is a great project for the advanced electronics hobbyist/guitar player. I think there are quite a few of us out there. Obviously you can buy this functionality in a “Digi-Tech” stomp box with no soldering, troubleshooting, or swearing involved but heck… what fun is that? By the time you complete this project you will have built:
- A guitar sub-octave generator
- A guitar to gate & trigger generator
- An audio mixer.
- Two AD/AR generators.
- Two Triangle wave LFOs.
- A 12dB/octave lowpass VCF (Voltage Controlled Filter)
- A exponential response VCA (Voltage Controlled Amplifier)

Awesome effects with ‘made-it-myself’ pride – could be a good way to familiarize yourself with the synth basics as well – Link