Though you may not realize it yet, you are really asking the old, "What is the sound of one hand clapping?" Zen riddle here.
An old legend, recounted in the book "Japan's Ultimate Martial Art" by Darrell Max Craig attributes the following quote--which you might find useful--to jujitsu master Komto-Akuda;
"Before you get into the water you must first learn to swim. Remember, if you are going to be my student and search for the answer of one hand, I can only show you the way. I cannot teach you; you must teach yourself. The sound of two hands clapping is one of the most vital elements in the art of Jujitsu as well as in Zen. Always remember, when the hands are clapped, the sound is heard without a moment's deliberation. If there is any room left even for a breath of air between these two actions, there is interruption. The sound does not wait and think before it issues; one movement follows another without being interrupted by one's conscious mind."
I know this is probably an esoteric and unsatisfying answer, so I'll put it in practical terms...
The depth in Jujitsu training is found in its ability to train the Jujitsuka to become his/her own teacher (a Learning Observer) and interact with the world in an intuitive and instinctive way. This intuition and instinct can only be gained through constant training (living in the moment of 'two hands clapping') so that, eventually, the student becomes so adept that he/she can ANTICIPATE events before they actually occur and live in the moment of 'one hand clapping' (which is the moment before the 'two hands' come together).
A high attainment, to be sure! However, just take a look at any Jujitsu master in action and you will see that they live to the beat of 'one hand clapping'. This is why their techniques are so fast, decisive, and effective. They jump to the top of the mountain in one leap while the rest of us are searching for a good path upward.
Sanchin is great, but the absence of a similar reference point doesn't limit the various Jujitsu ryu--it expands them.
However, if you really must have something like Sanchin to find depth and relevance in Jujitsu, then stand alone in a quiet room and then suddenly clap your two hands together. There you have your equivalent.
Naturally, this is just where I find the depth in my Jujitsu training. Ask another Jujitsuka and you'll get another answer! :-)
Ni Dan - Ryukyu Kempo/Yawara Jujitsu