DID trunks are quite common, both DTMF and even dial pulse. Our phone company has a lot of customers still using them. Many are migrating to PRI but there are a lot of older PBX's going strong. All the ones that I've seen are loop start.
A DID is basically a set of phone lines (FXS's) that your PBX sends back to the central office, you are sending the 48 volts towards the CO. You tell them how many digits you want to receive and you then send the call off to the extension. Usually companies require that you purchase a minimum of 4 trunks and you also have to get a range of PSTN numbers depending on how many extensions you want people to be able to reach directly.
One difference with a DID trunk is the ability to send a "wink" to the CO. DID trunks can be either immediate or wink start. With immediate the CO switch will seize the trunk towards you and send the digits, it assumes that there is a working connection on that trunk, usually dial pulse trunks are/were set this way as a default. As DTMF became available they came up with wink start. the original PBX's had a limited number of DTMF receivers as they were quite expensive. When a call came in on one of the DID trunks a receiver wasn't always available right away. So wink start was developed. When the DID trunk is seized by the CO the PBX will send a wink, a quick current reversal towards the CO to tell it to send the digits. If no wink is received then some CO switches will try the next trunk. DID trunks are also usually capable of sending a CO a reversal when the extension is answered, this will tell the CO switch when the extension has hung up and to disconnect the call if the caller hasn't yet hung up.
So, if you don't need wink start or the reversal on answer, then you could use a common FXS card back to the CO. All of this depends on what your local PSTN carrier requires.