Among the recent flood of retail openings on Madison Avenue is a trio of boutiques catering specifically to men who treat their wardrobes like investments.≠ Bottega ≠Veneta, which unveiled a women’s store in December, introduces its first U.S. shop for guys (23 E. 67th St., nr. Madison Ave.; 212-879-4182), its racks devoted to swanky suits and $6,000 croc messenger bags. Another Italian import, Cesare ≠Attolini (798 Madison Ave., nr. 67th St.; 646-707-3006), calls a 2,500-square-foot duplex its first Stateside home. The sportswear and bespoke suits within are handmade in the Attolini family’s Naples factory, but this is no mom-and-pop operationósuiting here can hit the $10,000 mark. Down the street, Swiss watchmaker IWC Schaffhausen debuts its Manhattan shop (535 Madison Ave., nr. 54th St.; 212-355-7271), full of the brand’s super-splurge timepieces ($5,000 to $50,000) and fancy dude toys (a remote-controlled airplane for, no joke, $39,000).