My first programming job in the 90s while I was still in college was building systems exactly like you describe (and they were as poorly built as you think hah). I worked for a small IT programming/consulting shop. We did small jobs like this in town in addition to installing networks, IVRs, etc... while working on larger software to sell (which is an entirely different/crazy story that involved burning CD demos and using a hand 'stomper' to label and then mail them out).