IVe put together a 4s 4S A123 26650 (or whatever their chinese made offshoot was? olevin power?) jumper pack that works great. Ive started a V8 Jeep Grand Cherokee with the main battery removed. It sounded a touch slower than the normal starter battery, but I did have ~10 feet of 6 or 4 awg wire and jumper cable clamps instead of a proper low resistance connection.
Since its a jumper pack, no BMS in mine at the moment, just use a hobby charger to balance charge them, and a 100A thermal circuit breaker (curve on it says its good for a 4x overload for 30 seconds) As you mentioned reserve capacity, the battery would only be 13.8 AH, only a "33 minute" reserve capacity. Vs 80-100 or higher for normal FLA starter batteries.
You can get a starter battery with plenty of power, but to get the energy in the battery for a good reserve capacity is $$$
As far as diesel engines, most definitely not
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I tried to jump a diesel skid steer and it just laughed at my 4s4p pack. Diesels need 100-200A to run the glow plugs/heater grid for 10-15 second, and then need to run a very large starter that has to crank a very high compression engine. I'd expect a jumper pack to need to do ~300A for 30 seconds to even think of starting a small (4 cyl)diesel, and 600+ for a V8. For a main battery with a good lifetime, 800-1kA + capability, even more for when its cold (diesel pickups come with 2 800+ CCA batteries for a reason)