i bought a couple of these on ebay a few days ago...- i do not expect they actually work- direct from hong kong...


http://cgi.ebay.com/USB-VGA-to-TV-Co...#ht_2723wt_800

at 30$ each i have no expectation - it says you can shift vertical and horizontal position of tv display- whatever than means.
has a loop through vga port.......

USB VGA to TV Composite/S-Video Adapter NTSC PAL
Convert the computer's VGA signals into the NTSC(NTSC 3.58) or PAL video standard
This converter supports 4 levels of flicker reduction.
Adjustable vertical and horizontal position of TV display.
Simultaneous VGA displays on both VGA monitor and TV with VGA pass-through
Full scan rate supports:
Scan rate up to 60Hz @ 1024x768 pixels VGA mode
Scan rate up to 85Hz @ 800x600 pixels VGA mode
Scan rate up to 85Hz @ 640x480 pixels VGA mode
USB power driven
Compact design to save space and best suitable for mobile users
Size : (L) 99mm x (W) 60mm x (H) 32mm