A "blur" filter for trv900 (or any other cam).

A few years back I came across an ad in some video magazine, that was claiming that the filter that they were selling will edd more blur to the background. They even have had pictures "Before" and "After". On those pics it really looked much different (I think there was an eagle on that picture :) ).
Anyway, if any1 please can help me to figure out what kind of filter gives that "expensive" lens look to the video - that'd be great!
Thank you.
Andy
P.S. I am not sure if it was just a filter, or an extra lense..., I was thinking about "mini 35", but it is WAY too expensive, and it requires the lense it self..., so if any1 have seen that edd or have any suggestions about the "zoomed-in-far-from-background" :) blur effect, with something that wont be AS expensive as "mini 35", pls let me know.

I think you're talking about a diffusion screen. You can't produce that effect with a filter alone. I've seen a company that sells this translucent screen you can place behind what you are filming and it blurs everything behind it. Kinda hokey, if you ask me.

You could also try a chroma key of your subject onto an out of focus background... :)

Thank you for your help, but no, I meant just a zoom in effect, when the background gets blured. The thing is that in order to do it I have to zoom in all the way (to get a decent blur of background), but with other lenses (if it was interchangable), or with some extra extension lens I hope to acheave this effect without the interchangable lens.

The closest I have seen to what you are describing is probably the "Cokin" filter system. You buy an adaptor and a holder (about $20) then buy whatever filters you need. Look at their web site they have a large selection.
Here http://www.cokin.com/ico3-p1-3.html
or here http://www.cokin.com/ico3-p0.html.
You could also try add the effect while editing. most editors have filters that you can play with.