A Singer 201 is said to run over 1100 s.p.m. (from the Sewalot site). I don't think mine does, mine runs a tad slower than my 99 for some reason, both have the same motor. I guess the motor on mine could do with a thorough clean and regrease, but I haven't needed higher speeds. I don't know if there's any point in fitting on a faster motor for me, I like the low noise motor, but some of the new replacement motors are faster.
The old Berninas has about the same max s.p.m. and dependably with the original motor setup. I don't think of my old Bernina 730 Record as slow, it's faster than many newer machines. It's only for some types of zigzaging I floor the pedal if at all. If you find a 740 Favorite (and related models with the rotary hook) they are speedier and stronger. I think the 740 has 1300 or 1400 s.p.m, and it can handle the speeds. It's a flat bed and behaves differently than the freearm models (which has the occilating CB hook).
The old Elna Supermatic is measured to reach 1500 s.p.m by a couple of members of the vintage Elna group. These have internal motors and I don't think there's any point in trying to replace it or speed this model up. The stitch speeds are measured after a thorough clean and fix up.
I have worked on a few modern machines (current models still in production), some of them are slower than my vintage machines. I'm guessing around 1000 s.p.m is the average speed on a domestic machine (both vintage and new). A lot of the modern medium range models is listed at maximum 800 s.p.m. I can't find anything specific on your Elna. Some modern quilting and embroidery models boast of having between 1.500- 3000 stitches per minute, but you have to search out specifically to find these speeds. They are in the pricy range too.
The maximum speed on smaller domestic machines are on light cotton fabric, heavier and denser fabrics will slow maximum speeds. I personally have a limit to what I find practical when it comes to speed, and for anything like clothes and neat stitching a long curtain edges I don't go above medium speed. I floor the pedal on my 201 some times, but as mentioned I think it's around 3/4 of it's optimal speed. It's hard to compare models by motor amps and stitches per minute, but it gives a rough guide. You cannot trust the specs given on replacement motors on ebay, but they might still be good.
Roger on this forum has this neat vintage industrial in a small cabinet. It might be a high speed model, not too large, and I am envious. I can't remember the model number.
The standard Singer belt driven motor for domestic machines wasn't very powerful with its' 0.3 amp, all the model 15s and 201s had this motor. It stitches anlong at a nice speed though, very pleasant an less noisy than many newer machines. The old Pfaffs and Husqvarnas generally had a stronger motor (at least the rotary hook models), and I think some had an extra strong motor.
Edit, here's
the thread on Rogers machine, I think this is the one in a nice brown cabinet; not too industrial looking at all.