I don't know if what you saw was aftermarket or not, but there were smoothie-type (88-98 style) power mirrors available on 91 Suburbans. I had a truck in for service that had them - I phoned the dealer immediately to find out - and they were original equipment!
They looked okay at a glance, but half the mirror hangs up over the top of the door so that you actually see the backside of it through the side window. I guess its a matter of personal taste.
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'66 C10 longstep - Clifford equiped
'84 C20 Suburban 6.2L - awaiting 4x4 conversion
'91 V3500 Crewcab - awaiting diesel swap
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