it's an old post, anyway, FTDI provides complete working solutions, not only development board (like a VDIP1 against a VDRIVE!)
it's cost is variable, you can search at mouser.com, the chip alone does not have a firmware programmed, so you need to program it by USART.
personally I got one from Ukrania (with ebay) a VMUSIC1 for about 50$us (including shipping) it was already with the last firmware version...
you can upgrade the firmware and also customize a little the firmware, but sadly you can't make your own firmwares...
as it said on the vinculum web page, they are developing a new VNC2 which could be programmable (as they have the compiler for that new chip.) maybe wait a little more (to get more info and examples!)