Bespoke Empire maps
Bespoke Empire maps in the style of the existing maps will be relatively fast to produce. You choose what areas, colour, features etc you want and I'll adapt the existing master map. E.g. you only want cities, rivers, and Bourse resources, with the resources in red. No problem.
IC, all maps in this style have been produced by the official Imperial Cartographer.
An adaptation of one of the Empire maps is likely to take only an hour or two to produce. If you want a completely different style of art on your map (e.g. to have produced the map yourself IC), the costing model will be much more like a map from scratch.
A few important points about Empire maps:
All maps that are not released by PD via the wiki are unofficial. So, yes, I can totally make you a military map of Holberg with where the walls are and strategic towers and roadways etc. However, none of this information will be canon. Basically, if you want to add detail of any kind to Empire maps (villages, ports, vales, streets) you must accept the possibility that a later official map or plot map will contradict your unofficial map. That said, Empire is a points of light setting, and is unlikely to ever release official maps at e.g. a street or village level. But you commission a new Empire map on this basis.
Maps from scratch
I can make new maps in any style. How this usually works is you give me your sketch and perhaps a few links to the style you're going for. I then artify it and make it look pretty. I'll also do some geography sense checks to make sure rivers aren't flowing uphill etc.
These can be very time-consuming, especially if there's a lot of text. It varies hugely depending on level of detail, but a map like the one above would likely take around 10 hours.
General advice for creating fantasy maps:
Fine geographical detail is the enemy of story. Leave your campaign setting with some wiggle room, it will make life much easier for your plot writers, and give your players more freedom too! Your map should aim to inspire and excite, not limit.
Get a good idea of how the artwork fits into your overall setting. E.g. a steampunk setting might feature a map that's much more like a technical drawing than the watercolour style above.