There are 3 roads to non-genuine Newmans -
1. the cheapest/easiest option, buy a rep ($300+)
2. the moderately expensive/difficult option, build an ETA 7750-powered franken ($1,000+)
3. the expensive/difficult option, build a Valjoux 72-powered franken (genuine 62xx Daytonas are powered by [Rolex] modified V72 movements) ($3,000-$6,000+)
3a. buy a pre-assembled V72-powered franken from 1 of the aftermarket parts sellers & have it professionally overhauled (these things often look like they were assembled by monkeys & arrive in dirty/dodgy condition) ($3,000-$4,000+)
For option 1, do your research before you begin! Spend time looking at genuine Newmans on gen watch sites & ebay. Learn the differences between versions & Oyster/non & collect pics of gens for comparison. Then, browse the dealer listings in the Watches section. For option 2, beginning with the same rep, swap out as many of the rep components with better aftermarket or genuine Rolex components as you can afford. For option 3, get a 2nd (or 3rd) job, start saving & pulling your hair out. At the same time, start searching online for a used V72 movement & have it properly overhauled. Then, buy an aftermarket case, dial/handset & bracelet. Optionally, if you have sufficiently deep pockets, you can replace the aftermarket crown/tube, crystal, pushers, dial coronet & bracelet with genuine Rolex components.
Whichever way you go, there are many threads on RWG that detail members' previous project watches & be aware that as the price rises, so too does the complexity & likelihood of problems. Rarely, do the high end franken projects go according to plan. So be prepared to deal with the inevitable problems, cost overruns & detours along the way.