You're looking for a Shimano SL-M310 or similar. They made 7-speed under-bar triggers with no display window. The "Rapidfire Plus" line often had minimalist models. Check used parts sites or local co-ops. Sawing off the indicator will work, but be careful not to damage the internals. It's plastic, so a fine-tooth hacksaw and file will do the job.
All the SL-M310s have gear indicators. The few others that I found without an indicator are 12-speed.
I have a junior hacksaw if and when I decide to try cutting the indicator off. I was concerned about what's inside it getting damaged. Heck, if I ruin it, I'll have to get another one.
I had replaced the cowhorns (It's an Electra cruiser) with different bars but the Shimano 7-speed shifter wouldn't work with them because of the downward curve. It needed longer bits of the bars at the end. So I put another handlebar on it, last night. It's better but the ends of the levers encroach into my finger space. I had already put an above bar shifter on it but I didn't like it, which is why I put my other shifter back on. I'm probably being too picky. I just need another 8 mm of space, and it's the indicator which is preventing it. Or if it comes to it, I could put the cowhorns back on. That ought to fix it. 😃
