Talking about NUC's I ordered one, they seem pretty slick with the new i5 skylake chip. I am installing 16gb on it and an SSD as well. They are tiny as shit and you can use a bluetooth mouse/kb. So the only connection would be the monitor and power. (Wireless internet for network)
I bought the 6i5SYH and 16GB of ram for it and put in a Samsung 840 pro 256gb SSD I had laying around. I am replying to this thread with it now. Man it is so small but it packs a punch. One of these units would work fine as a day to day PC, using your trading software etc..
Simply judging by the name of this thread I already see that you overpaid damn a lot for some build which called "Trademaster" and that's really it for any possible situation. Better to do custom machine, it goes way cheaper anyway in any case.