If I were in your place (from what you have said), I would not agree to misrepresent your relationship with this person and furthermore I would seriously reconsider whether I would want to continue to deal with someone who is willing to do this. It would be hard to believe that I was not being mislead by him. A reputation is easy to lose and hard to recover.
In this world, it's not uncommon for people to present sub-contractors in this light. I personally don't think this is the optimal setup, and if I were in your shoes I'd not want all my eggs in one basket, so to speak. But as long as things are what they are, I don't see much harm in going along with this.
Let's say you agree to his wish. What's in it for you? A promise for more projects in the future? Maybe, as long as you agree to present yourselves as his company. The only reason I see why you would agree to his wish is fear (of loss) and there's something I learned with great pain: when I act out of fear, I end up regretting it.
Then there's the fact that by agreeing with his wish you would essentially be lying. I read an essay on NH a couple of months back about an entrepreneur that had a golden rule: never lie! His reason for adopting this rule was that by lying you are telling your brain that things are different than they are in reality and so your brain starts operating with false assumptions and soon enough your thought patterns adapt to the lies and you disconnect from reality in various ways. After the disconnect occurs your brain cannot offer you solutions to the problems you face in reality because it has accepted the fake reality you've presented to it (the one created by the lies). That's it in a gist. Here's the link[0].
Best of luck!
[0] http://boss.blogs.nytimes.com/2014/03/11/the-surprisingly-la...
That's probably the case anyway. Client A hires Agency Z to do project Q, then Agency Z subcontracts (some or all) of the work to Team D. Agency Z is always going to be the primary interface to the Client anyway in a situation like that. If he's got the pipeline and can bring work in, and Team D doesn't have the sales/marketing mojo to bring in work on their own, they might as well just go along with it.
That said, I'd encourage them to look for ways to break their strict dependence on this one intermediary... I've seen Bad Things happen when a company overly depends on one customer and then that customer goes away for whatever reason. Building a sales funnel and getting deals takes time, especially starting from scratch.
If you need the money now, you can say YES but eventually you will have to either replace this guy or look for projects yourself.
It sounds like he's getting paid by the client first and then he'll pay you? If this has been the arrangement in the past and he paid as agreed, maybe. But if this is a bigger project, as the client wants to visit, you should hammer an agreement to get paid promptly in stages. You don't want this risk of him simply running off with a big payday.
A guy that brings you random spec work that includes you as "his company" in his pitch is a lot less likely to ditch you than a guy that brings you random spec work who represents himself as a one-man band whilst subcontracting the work to you, or for that matter a regular small business client contracting with you.
Sadly, the intermediary's request shows his true colors. Suggest you make it a top priority to find a new Strategic Partner/Rain Maker/Business Development executive to represent your team. Frankly, this could be a great opportunity to up your game. Adios Intermediary!
This guy is going to lie to his client and wants you to lie too, but you feel like you can trust him (to provide you with more work).
You are his partner.