Netcoin -> 3d logo for marketing purposes, 2d logo for CMC and Coinwarz. Actually if you look closely they do use the 3d logo for CMC/Coinwarz!
I think it's not a difficult task to create 2 versions. The model is rendered in C4D and can be seen by different angles. A little bit of photoshop and voila
EDIT: ^^ well exactly
That's all well and good, but thats more work and leads to brand confusion. Why have two types of logo, when a flat version is all you need. The Netcoin logo is sht btw. I prefer a web2.0 type of look, much like the original BitCoin logo. This is easily reproduced in vinyl stickers, stitching on T-Shirts etc etc. Where as the Netcoin logo is a complicated mess, as soon as its reduced to say a 50 x 50px gif, the wording is unreadable and the colours bleed.
Check the Quarkcoin logo competition thread. Each entry has a 3d physical coin coupled with a 2d flat illustrator design.