Just seen that like most, I completely failed to answer anything other than the title.
Dave Yates’ prices here: http://www.daveyatescycles.co.uk/custom_bike_frames-Prices-52.php
Which I think are about on a par with others, powder coating will always be a good slice cheaper, and if it comes out as nice as Vortexracing’s Kona, why not? Harder to strip/blast off if and when you want a refresh, though.
Decals, try here http://www.hlloydcycles.com/
or Gil at the cycleshed has been recommended on here.
Or keep it understated and just get a headtube badge from someone like Geoff Moorhouse – http://www.heavygoods.org.uk/Headbadge.htm – the Dekerf one in the middle at the bottom is the one I had made for mine up there ^