The cheapest, most direct route is probably to have a millwork shop surface and joint one edge of your stock for you. Otherwise, I think you've hit on all the likely (or unlikely) possibilities. Rental seems like a long shot, since a jointer of any useful size would be difficult to move, easily damaged and somewhat dangerous. You might see if there's a community college or vocational school that has a woodworking program where you could take a class. You could buy a used one, tune it up and have the blades sharpened, and maybe re-sell it when you're done.

You could use a hand plane with a sharp iron. The plane is much quieter and safer than a jointer and not that much slower.

Have you considered using a router?

Pooh Bear

Here is a link that might be useful: Edge Jointing with a Router

Thanks for the comments and suggestions, everyone. I don't have a router, have never used one, so I wouldn't feel at all confident about using one for this purpose. Just me, I'm sure that a skilled user could do it just fine. I will be looking into having the millwork done; I've done that in the past for projects and it seems to work out pretty well. I have a couple of places to check locally. I'm also going to start a new thread on finding furniture makers in my area. Steve

Invest in a #7 jointer plane.
It should only take a couple passes to make a perfect edge.
Routers leave scallops in the edge (like a jointer) and you still need a pass with a regular old plane to get the best joint.

If you're building a tabletop, I recommend flattening the stock on a jointer before planing it, as this is the only way to ensure that the stock is free from twist. Other than plane twice as much as you need and only use the best ones.
The glue-up will only be as flat as the most twisted board within it. The necessity of square straight edges is requisite for achieving a neat joint from board to board, but it will not make up for stock that is not flat. A #7 (or #8) jointer plane will give you straight square edges only if you know how to use it. Learn on pine before advancing to your project material.
I'm a ways west of Frederick, MD, and you can use my jointer any evening or weekend, if it comes to that and you can't find anything closer to you.

Casey

Thanks for the comments, and especially to Casey, for your kind offer to use your joiner. I probably won't be going ahead with this project as I think we are going to accept an offer from a local craftsman to build us a table. For the reasons given in Casey's message, I was a little reluctant to undertake this project without the propoer equipment (and experience!). Thanks again, Steve