"Large" Seven-Segment/Scoreboard Controller Design (and Questions!)

Yes, I was trying to describe a design akin to the Sparkfun design (albeit a bit more weatherproof). I'm trying to avoid paying obscene amounts of money for digits like KE7GKP's 12-incher ($50 for one digit!). I intend to use discrete 5mm LEDs, wirewrap the interconnections, and then ultimately solder the power leads to the board permanently.

The circuit board and components currently come somewhere around $30 total. I suppose in that respect it's a bit of proof of concept as to how economically such a scoreboard can be built.

TLC5925 @ 3 = $4.50
ATMega328 = $4.50
Circuit board = $2.50 (each, quantity 10 required from Seeedstudio)
5mm LEDs @ ~150 = $7.50
....plus wire/resistors/headers/common stuff = $10.00.