This is the one RNO was asking about. Sorry it took so long RNO, slipped my mind.
So it doesn't take me all day to redo another, I'll try to deconstruct the image I posted before. It does get time consuming to get it perfect.
Here's the finished image again.

I'll get rid of the background as it isn't needed... ungroup the lettering and remove the black shadow background.

OK let's start the explanation moving beginning to end but I'll still need to deconstruct.
Make your object or lettering, whatever it is, and use Inkscape to do a perspective on it.
Make a duplicate.
Line up both one above the over.
Give one a blur. I used 1% blur on the one above.
Now the hard part. You need to use --> Object --> Mask --> Set like you would when you do a reflection. These are the two masks I used. One for each. The top mask was used on the blurred text.

Lining these up is easy with --> Align and Distribute. Getting the mask right is the hard part.

You got to pretty much play around with doing the mask, fitting the objects together to see if it looks right.
Hope this helped.
Cheers