Secure, compact stop blocks

Hi folks,

I plan to build a version of Fritz and Franz (an awesome sliding table accessory).

http://www.youtube.com/watch?v=DqzVglze9Nk

It will incorporate stop blocks and that is where my question comes in. I am looking for secure stop blocks that are also fairly compact side to side since I don't want to make Frits and Franz too wide.

I have not had good luck with flip stops (slop) that cost less than hundreds of $ (not going to happen).

The Kreg production stop seems secure enough, but it is a bit wide. I am looking for a top-loaded stop like the production stop if possible.

http://www.amazon.com/Kreg-KMS7800-S...reg+production

I tried calling Peachtree about their Universal L-shaped fence stop, but the person on the phone did not even know what a stop block is, so clearly could not tell me how secure this block is.

http://www.ptreeusa.com/ttrack_list.htm

Any good ideas? I can adjust the height of the track from about 1.5" to 3"

Thanks,

Jerry