Ughadoo

You can also use a multi stage Ripple counter; every stage will divide the input frequency by 2 and so a 16 stage counter will output a frequency of 61.03515 Some extra logic will be necessary to correct the output and to further divide to 10 Hz. CMOS Ripple counter datasheets:CD4020BC.pdf

It can be a shockley, but its behavior when voltage drops to +10 V is a bit weird;

A 4060 is even better than the 4020 because you can use its internal ports to create the 32768 kHz, as in the circuit and datasheet below: CD4020BC.pdf

A very simple and accurate way is through a 32768 kHz crystal oscillator followed by a clock divider. dt26_dt38.pdf

Switching diodes are fast diodes that show low losses when used at medium/high frequencies.

I tried today and it worked. You can try this link: http://www.dimensionengineering.com/DE-SW0XX.htm

That's not a good argument;

Roomi, as audioguru and indulis already said, there is no problem to exchange a large capacitor to some smaller types in parallel. ESR and parasitic inductance will be lower with a parallel capacitor assembly, but this will not affect its performance (in fact, if this was a switching power supply, it could even improve the performance). Of course, price and space will be different, but it's better than not assembly the project due to a impossible to find piece.

Analog voltmeters have a resistor in series with its coil;

A PNPN device is a SCR thyristor, as the title says;

Yes.