V600i

The V600i is a K600 rebranded for Vodafone:

It is very similar to the K750i, even down to the batteries being interchangeable. The software is also pretty much the same, except for the requisite UMTS features.

Pluses:

• Small Size (only a couple of millimeters thicker than the K750i)
• Standard SonyEricsson power connector (not the newfangled one they're using on the K750i).
• Great screen (same size as K750i, but smaller than the V800), readable under direct sunlight as shades of gray.
• Excellent Bluetooth features (and 3G data performance)
• RDS-enabled radio.

Minuses:

• "Sub-mini" USB data connector
• 1.3Mpixel camera - plastic flap opens too easily
• Side keys (they require long presses to activate, but are still prone to accidental activation unless you switch on the keypad lock - it isn't on by default).
• Non-standard (i.e., SonyEricsson) stereo headset (same as the V800's)
• No memory card slot.

Dial-up Networking, Serial Port, HF Voice Gateway, HS Voice Gateway, OBEX Object Push, OBEX File Transfer, OBEX SyncML Client, OBEX IrMC Sync Server, Mouse & Keyboard

Adding iSync support:

(Based on this hint. See the Resources section below for an alternative.)

Again, this is pretty much identical to all other SonyEricsson phones, so it's strange that Apple can't roll out a quick update. Before adding your phone to the Bluetooth device manager, modify PhoneModelsSync.phoneplugin/Contents/Resources/MetaClasses.plist (inside iSync.app) to include the necessary identifiers as such:

<key>com.sony-ericsson.K600</key>
        <dict>
                <key>Identification</key>
                <dict>
                        <key>com.apple.gmi+gmm</key>
                        <array>
                                <string>Sony Ericsson+Sony Ericsson 600</string>
                                <string>Sony Ericsson+Sony Ericsson V600</string>
                                <string>Sony Ericsson+Sony Ericsson V600i</string>
                        </array>
                </dict>
                <key>InheritsFrom</key>
                <array>
                        <string>com.sony-ericsson.irmc5</string>
                </array>
                <key>Services</key>
                <array>
                        <dict>
                                <key>ServiceName</key>
                                <string>com.apple.model</string>
                                <key>ServiceProperties</key>
                                <dict>
                                        <key>AlternativeNames</key>
                                        <string>V600i</string>
                                        <key>ModelName</key>
                                        <string>K600</string>
                                        <key>PhoneIcon</key>
                                        <string>SEK600.tiff</string>
                                </dict>

WAP Headers:

(to be filled out later)

• mobile.feisar.com has iSync plugins (which cleanly apply many of the changes outlined above)
• InfoSync