This is the sort of thing I'd like to set up, but what this company is
offering, like a number of others I've found, is a complete solution.
So they supply the PCI card, the cameras and the software (and cable
and stuff).

How about this off eBay - They are always avalable!
http://tinyurl.com/rz0f

Here is some info if you can't be arsed to look at eBay

Excellent Quality DSR Card (4 Channels) for Home/Office surveillance and
security.
Each PCI card supports 4 BNC/RCA cameras, and can chain up to 4 cards per
PC, i.e. 16 Channels per DVR PC.

This robust DSR Card supports sophisticated functionalities including:
- 16 channel recording (using 4 cards together)
- remote monitoring through Internet / LAN
- time-stamped recording
- motion detection



Specifications:

DSR Card
full resolution video: PAL (768x576), NTSC(640x480)
generic PCI slot compatible available in all PCs
4 x BNC/RCA Video Input
1 x DB25 female connector for Alarm triggering
1 xDB15 female connector for Alarm triggering
Video Server Software

runs on MS Windows 98/2000/NT (XP and 2003 is not officially support, but
tested by our engineers, and it runs OK)
low hardware requirement: PIII 450Mhz, 128Mb RAM, 10GB HDD, Network
Card/Modem
full resolution video: PAL (768x576), NTSC(640x480)
configurable up to 16 camera (simple insert 4 DSR cards on the same PC)
16-channel digital multiplexing
real-time digital video compression
7x24 remote access service through TCP/IP(Internet) and/or modem dial-up
user access right control for different operations
video playback using Media Player
Pan/Tilt/Zoom Control
motion detection recording
alarm triggered recording
programmable timer recording
multilingual capability
Remote Monitor
runs on MS Windows 98/2000/XP/2003
extreme low hardware requirement: PII 233Mhz MMX, 64Mb RAM, 5GB HDD, Network
Card/Modem
password login and event log
remote online video viewing
local recording of video at remote machine
remote historical video playback (both local and server video records)
alarm alert function


Sparks...