G`day Rosco, I am new to cnc myself so i cannot offer you any qualified advice.
However i have been cruising this site for about a year trying to learn as much as possible before i take the plunge and actually buy a machine.
From my limited knowledge you would need a machine size of 4ft x 8ft.
The leading names for low cost cnc routers in the USA would probably include - Shopbot, Shop Sabre, Ez-Rout, K2. There maybe others but these are the names that spring to mind. It would pay you to visit their websites. Shopbot have an excellent forum.
There are also Chinese machines available such as sh-cnc.
A very much admired software is V Carve Pro from Vectric and it is quite low priced.
Good luck with your business venture.