Though, if you want to make it really simple... there's a mechanical arm that must be pushed or pulled. There's also a pressure limit you want to set. The correctly sized pressure actuator would move that arm as soon as you pressure limit was hit, reducing blade angle, and limiting boost. With a little dampening perhaps, the turbo would spool quickly up to XX PSI and hold that pressure throughout the rpm range. The only problem being if there is a failure the turbo would default to closed. So you'd have to have a overboost protection system... kinda like the Mercedes overboost protection system. The downside would be a slight exhaust restriction... which may or may not be worse than the current turbo. Oh, and the uncertainty of what the IP does when you have full boost and low throttle position.

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I suggest we solve high gas prices with environmentalists... unfortunately they don't burn well.
1982 300CD, 220K miles: This vacuum system will be the death of me yet! (OBK #26)
1977 F150 400 C6 2wd, 10.2 sec 1/8 mile with 2.75 gears.
1965 Mustang. Mostly stock... LOL!
2001 Ram 2500, cummins, 5spd, 202k miles.(girlfriends)