For every coin :-
1x rock pi 4 model b starter kit, storage and shipping- $263.23
May i ask why you decide to use a dedicated pi for each coin ?
Why not simply build a small server farm ?
You'll get way more computing power with 1 high-end "computer" (for ~1800$), than you'd get with 7 pi's (for the same price approximately).
Computing power is only a small concern among a myriad. For personal use perhaps that would be a great solution, but this is now a situation that requires considerations and possibilities that would affect an enterprise.
This system offers more security, redundancy and developer friendliness while maintaining high performance for each and every coin, no compromise. Apart from handling exchange deposits and withdrawals , many of the apps on he platform will use these wallets too, so the more robust the system, the better.
To protect the system, and to keep my idea unique to me i will not discuss the exact specifications , architecture or release any of the code that keeps this system running. Suffice to say
I took into account the following :-
1) Dependency management
2) Performance issues from running too many daemons in a server .
3) Prevent a single point of failure for multiple daemons
4) Security
5) Maintenance is easier when I only have to take down a single sbc for a coin. It does not affect the rest of the wallets.
6) Developer friendly (so many scripts already written)
7) Lower power and cooling requirements per coin, this system can even be solar powered, or moved without taking it offline.
It's unique to me, it's nice to come up with one's own ideas and implementations once in a while.
I can't stress enough how secure and incredibly redundant the system is in it's full form but as i said, it's specifics , especially on the hardware security and software side cannot be shared publicly