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Check again on the Hogue site, IIRC, they offer thin "aluminium grips" for various guns. Some even have a combo wood/brushed SS look.
Factory plastic grips or the above (if they make them for the P229) are gonna be your best thin grip, as wood grips look best, but as mentioned, they are right up there in width as the rubber panels, maybe even a bit more wide.
If Hogue doesn't offer the thin aluminum grips, I'd bet some one out there makes them, just gonna have to ask around or do a Google search..
Ls