Something I have pondered for quite some time since I experimented with pitch-shifting devices for my guitar, everything from an SB Live! sound card to various

Something I have pondered for quite some time since I experimented with pitch-shifting devices for my guitar, everything from an SB Live! sound card to various digital effects pedals - they all introduce insane amounts of warbling the further from the original tuning you go. Would this sort of analog-digital circuitry or something similar possibly work to build a pitch shifter with high enough resolution to effectively allow full audio range pitch shifting of source audio without warbling? Of all the things I've tried, the SBLive! was actually the best, holding semi-stable 2 full steps down on my guitar. Everything else was fairly nasty after a full step.