If it were my business I'd start out with ordering a couple SPS Varmint's & Tacticals, in .308 and .223. Then I'd order some McMillian A5's and some AICS stocks. Put them together for a decent price with bolt knobs and pic rails and go from there.
The problem is there are many custom rifle builders with alot of inventory right now, How will you compete with these guys? I think a great niche to start out in is the "affordable tactical stuff". IMHO opinion if you started getting into full blown customs and price points were the same, why would I buy off you when I could go to someone with a current reputation like ATRS for example. What would set you apart from the rest???
Start with the common hot commodity stuff first, and perhaps some parts too... Mags, pic rails, scope mounts, actions etc.