iPhone4,1 とか iPad3,1 とか取れるけどどれがどのデバイスなのかわからなかったので、一覧を探してみたらあった。
http://stackoverflow.com/questions/448162/determine-device-iphone-ipod-touch-with-iphone-sdk/1561920 にある https://gist.github.com/Jaybles/1323251 によると
if ([platform isEqualToString:@"iPhone1,1"]) return @"iPhone 1G";
if ([platform isEqualToString:@"iPhone1,2"]) return @"iPhone 3G";
if ([platform isEqualToString:@"iPhone2,1"]) return @"iPhone 3GS";
if ([platform isEqualToString:@"iPhone3,1"]) return @"iPhone 4";
if ([platform isEqualToString:@"iPhone3,3"]) return @"Verizon iPhone 4";
if ([platform isEqualToString:@"iPhone4,1"]) return @"iPhone 4S";
if ([platform isEqualToString:@"iPhone5,1"]) return @"iPhone 5 (GSM)";
if ([platform isEqualToString:@"iPhone5,2"]) return @"iPhone 5 (GSM+CDMA)";
if ([platform isEqualToString:@"iPod1,1"]) return @"iPod Touch 1G";
if ([platform isEqualToString:@"iPod2,1"]) return @"iPod Touch 2G";
if ([platform isEqualToString:@"iPod3,1"]) return @"iPod Touch 3G";
if ([platform isEqualToString:@"iPod4,1"]) return @"iPod Touch 4G";
if ([platform isEqualToString:@"iPod5,1"]) return @"iPod Touch 5G";
if ([platform isEqualToString:@"iPad1,1"]) return @"iPad";
if ([platform isEqualToString:@"iPad2,1"]) return @"iPad 2 (WiFi)";
if ([platform isEqualToString:@"iPad2,2"]) return @"iPad 2 (GSM)";
if ([platform isEqualToString:@"iPad2,3"]) return @"iPad 2 (CDMA)";
if ([platform isEqualToString:@"iPad2,4"]) return @"iPad 2 (WiFi)";
if ([platform isEqualToString:@"iPad2,5"]) return @"iPad Mini (WiFi)";
if ([platform isEqualToString:@"iPad2,6"]) return @"iPad Mini (GSM)";
if ([platform isEqualToString:@"iPad2,7"]) return @"iPad Mini (GSM+CDMA)";
if ([platform isEqualToString:@"iPad3,1"]) return @"iPad 3 (WiFi)";
if ([platform isEqualToString:@"iPad3,2"]) return @"iPad 3 (GSM+CDMA)";
if ([platform isEqualToString:@"iPad3,3"]) return @"iPad 3 (GSM)";
if ([platform isEqualToString:@"iPad3,4"]) return @"iPad 4 (WiFi)";
if ([platform isEqualToString:@"iPad3,5"]) return @"iPad 4 (GSM)";
if ([platform isEqualToString:@"iPad3,6"]) return @"iPad 4 (GSM+CDMA)";
if ([platform isEqualToString:@"i386"]) return @"Simulator";
if ([platform isEqualToString:@"x86_64"]) return @"Simulator";
で良さそう。