My suggestion? Put on friction shifters and learn how to use them. Once learned, problem solved. And now you can change wheels, cassettes, number of cogs, rear derailleurs ... doing nothing more than adjusting the limit screws and perhaps the cable tension. Or, try one of those radical new ideas like SunTour's Power Ratchets or the Simplex Retroshifts. (Power Ratchets max out at 8 cogs. Teeth are not fine enough for narrower cassettes. I believe the Rivendale shifters are similar but with finer teeth. If I went that route for my 9-speed, I'd try them. But I am still on friction.)
Of course there are many excellent reasons why this is such a bad idea. For one, it doesn't work. The 60 years or so of just friction shifting were a nightmare. That anyone could ride something like the Tour de France on them is incredible. So dangerous. Taking your hands off the handlebars? No one does that now! (Those waterbottles you see on race bikes? Just as full when they finish as at the start. No one would ever reach down to grab one.
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Edit: Friction shifting might be like walking. Hard to learn later in life. I wouldn't know. That was all I rode when I was 13.