Sony just released their 7" PIV and only costs $199 which is about how much you would spend on the LCD alone if you were to build your CarPC with separate components. Here's what $199 will get you (Dash spec sheet):

Power Requirements : AC 120 V, 0.6 A,60 Hz
Internal Memory : No User Accessible Memory

Video
Format(s) Supported : Windows® Media Video 9 (up to MP@HL 1080p)
Microsoft VC-1 (up to AP@L3 720p)
MPEG 4.10/H.264 (up to MP@L4.0 1080p)

Hardware
Device Support : Accelerometer supports Vertical Flip
Digital Ambient Light Sensor
Real Time Clock with Battery Backup

Inputs and Outputs
Audio In : Microphone
DC-In : 9.5 V, 1.5 A, 14.25 W
Headphone Output(s) : Headphone Jack (1 Vp - p)
PC Audio Input(s) : USB 2.0 Mass Storage Class

Wireless/Networking
Wi-Fi : 802.11b/g, 2.4 GHz WPA, WPA2, WEP Encryption WiFi Certified

Weights and Measurements
Dimensions (Approx.) : Approximately 7-7/16 x 5-5/8 x 2-3/8" (WHD)
Weight (Approx.) : Approximately 1.2 lbs
System Requirements

General : Broadband internet and wireless network connection required. Select content provided, subject to change. Video quality, product and picture size vary and are dependent upon broadband speed and delivery by content provider. Certain apps may require registration or account verification using a personal computer with internet access. Fees may apply to certain optional content.

Display
Native Resolution : WVGA Resolution (800x480)
Screen Size : 7.0" (measured diagonally)
Technology : Projected Capacitive Touchscreen (Gesture and Multi-Touch)
Digital Ambient Light Sensor

Audio
Format(s) Supported : MPEG-1 Layers I, II, III/MP3 (up to 320kbits/sec)
MPEG-4 AAC-LC (up to 192kbits/sec)
Windows® Media Audio 9 (up to 384kbit/sec)
Speakers (Total) : Stereo Speakers


Sadly no BT to make it a hands-free device for your phone and no GPS to make it a PND but both may be possible by connecting your phone into its USB port.

The device runs all of over 1000 apps designed for the Chumby and apps can be created using Flash Lite and submitted to the Chumby store, similar to but probably not as convoluted as submitting iPhone apps.

Considering how compact and inexpensive the device is and fulfills most hardware requirements to make it a viable CarPC, can anyone see any drawbacks with using this as apposed to any current solutions?