The very last cassette decks made in the late 90s had Dolby S - taking the humble format's SNR up from around 60dB (on a healthy deck / tape) to 80dB. S was the consumer version of SR, which rivalled 16-bit digital in dynamic range (from memory, I think SR on a 1/2" reel machine could manage 90dB SNR).
Considering SR encoder / decoder modules are relatively affordable these days, what would stop you from using one on a decent cassette deck? I'm looking at upgrading my current deck for the purpose of recording vinyl. As with the classic cassette decks (look at prices on auction sites...), vinyl prices have gone mad. Records I bought for a fiver are now north of 50 or even 100 quid. I was thinking that a high quality cassette would be a fun way of being able to listen to them after a few G+Ts, without the worry of damaging the vinyl (there is also the cost of decent styli). Of course, I could use a decent ADC, but where would the fun be in that? No satisfying clunk from the solenoid. I've even nabbed a NOS Canon amorphous head for said deck. I've got my head, just need to find a deck
NB - the 215 is the best deck I've heard. I got one out of a duping house. It didn't record well, but it played like new.