Q. Which small mixers have high impedance inputs?

I recently read Mike Senior’s review of the Alesis Multimix 16, and he listed as one of the cons the lack of a high-impedance instrument input. I agree with him, but have been searching for ages for a small mixer with this kind of input and can’t find one anywhere. Is there one? The mixer isn’t actually for me, but for a musician friend who still records to eight-track cassette via an old PA and various pedals and outboard. He plays bass pedals and has an ancient drum machines, plus he sings and plays guitar and banjo. The outboard and the PA mixer are noisy, and as I transfer his tapes and mix them I spend far too much time on noise reduction and not enough on mixing and production. He is not technically savvy, and getting him to use several of the eight-track inputs is not a option, so I am looking for a mixer he can plug his instruments into and get a clean relatively noise-free signal from, to feed the eight-track.