[CrimsonGT]

It is definitely possible, but the main problem I can forsee is the map overview screenshots. Between CSS and TF2, there are probably about 100,000 maps made. I suppose if you only supported the official maps (even then there are a ton) it would be more feasible, but the overviews would be the most painful part. Coding it wouldn't really be overly difficult as you would just need to keep player positions updated between the game server and the web server.