Word for pending project or collaboration

The first word that came to mind was tentative (unsure; uncertain; not definite or positive; hesitant).

After reading more carefully, I think a better word to use would be proposed (to put before oneself as something to be done; design; intend), as you have both put this collaboration before yourselves as something to be done, but it is still subject to confirmation.

Would you like to tell me more about your ideas for our proposed collaboration?

Prospective? Apparently I need to enter another 20 odd characters to answer.

Potential conveys the idea:

• possible when the ​necessary ​conditions ​exist:

  • A ​number of potential ​buyers have ​expressed ​interest in the ​company. Many potential ​customers are ​waiting for a ​fall in ​prices before ​buying. The ​accident is a ​grim ​reminder of the potential ​dangers ​involved in ​North Sea ​oil ​production.

• Would you like to tell me more about your ideas for our potential collaboration/project.

Suggested, as in the suggested project we recently discussed

1. to put forward (a plan, idea, etc) for consideration: *I suggest Smith for 
   the post, a plan suggested itself*

Rationale:

Many of the answers here suggest a level of solidity to your collaboration that your original post doesn't necessarily support. You're only hoping to work together; it's only very loose that you may work on this, or, indeed, any other project.

So "tentative" suggests that something has been agreed in principle and it's pencilled in to a greater or lesser extent. Even "proposed" implies that you have an agreed subject and/or other defined parameters.

It feels to me like you're almost agreeing to agree, in that the first step would be to define what "project" means in this context. Depending on how much detail you discussed, then, I probably wouldn't go beyond "suggested" or "potential" as either simply reflects the possibility of the collaboration.

hypothetical

Also, hypothetic

assumed by hypothesis; supposed.

Random House