While it’s not an essential for using the 7D, I couldn’t resist buying myself an indiSLIDERmini fromStudio 4 Productions.
The indiSLIDER is about half a meter long and has a metal glide carriage with mounting puck. It’s probably not as long as I would like but I opetd for the mini version as it seemed the most cost effective to bring in from the U.S.
I haven’t had much of a chance to use it but the few testes I’ve done came out well.
The one issue it has is a tendency to wobble a little as you move it. You need to push a little against the puck to keep the camera from moving as you slide it.
I made up a couple of little mini bean bags so I can use it on the ground or a table, etc.
I should also mention that if you do order one of these, don’t expect too much feedback from the seller. I got nothing from Studio 4 at all, not even a “thank you for your order”, until an email told me the slider had shipped.