Actually those aren’t that bad. Prime has two fantastic options that are not listed on their site yet, but you can reach out to Mike Kearney. They have a leg extension and seated leg curl combo, and a leg extension and prone leg curl combo. I have a TuffStuff leg extension/seated leg curl combo that is pretty good and does the job fantastically well, waiting for the prime one but the feedback on that is fantastic. There are some other good options as well. Not all combo machines are good but the chances of finding a good leg extension/curl combo are pretty decent versus the hack/leg press combo.
According to Mike, they do not have a seated leg curl/leg extension combo. Only the leg extension/prone leg curl combo which is still really cool, I’m just biased towards the seated and wish it came as a combo.