Re: f-style as american icon
Instruments that America can make some claim for as "originator":
Ukulele (Hawaii's now part of the US) -- derived from Portuguese guitar-family instruments
Banjo -- derived from African prototypes (banza etc.), but brought to its present form and variations in the US -- 5-string, tenor, plectrum, cello, banjo-mandolin, banjo-uke, etc. etc.
Autoharp -- variant of European zithers, mechanical chording device patented by Chas. Zimmermann of Philadelphia in the 1880's
Carved-top guitar and mandolin -- application of violin-style arched, carved tops to mandolin and guitar family instruments, mainly initiated by Orville Gibson around 1890
Steel-string guitar -- derivative of gut-strung Spanish-developed instruments, enlarged body size, altered bracing patterns, early 20th century by Martin and others
Electric guitar -- attachment of device to electronically amplify string vibrations; Rickenbacker "frying pan" electric steel considered earliest prototype.
Resonator guitar (and other resonator instruments) -- design by James Beauchamp and the Dopyera brothers, Los Angeles, 1920's
Steel guitar, pedal and "lap" varieties.
Don't know about the Appalachian dulcimer, since there are German and Scandinavian fretted, elongated zithers that seem related, but its current configuration seems American.
Getting back to the original theme of the thread, I would hold up the F-style mandolin body as a significant icon of esthetic design, and cite its world-wide popularity. Since scroll and points are there basically as decoration rather than for acoustic enhancement, it really is a silhouette that has captured the imagination of musicians for its gracefulness and visual interest.
Gibsn: '54 F5 3pt F2 A-N Custm K1 m'cello
Natl Triolian Dobro mando
Victoria b-back Merrill alumnm b-back
Stradolin Vega banjolin
Sobell'dola Washburn b-back'dola
Eastmn: 615'dola 805 m'cello
Flatiron 3K OM