I'm thinking of starting a new website which will have a forum and a Wordpress blog on it. I already know a trustworthy company that can make me a forum theme but I'm struggling to find a decent Wordpress theme designer. I mean there are loads of options but finding out if they are trustworthy is much harder. What I want to do is pay for a forum theme and then get a Wordpress theme designer to copy that theme on my Wordpress blog so that the whole site works well together. I'm just not sure where to look for Wordpress theme designers. Does anyone have any recommendations?
Why do this? Wordpress has forum plugins, install one of these and you will have everything in one place. Or install a blog extension to your forum software - like UKBF has done.
Because I want the blog on the main domain and the forum on a sub-domain. Also why would I go for a second rate solution just because they are designed to work together? Wordpress is better than the Xenforo blogging addons and Xenforo is a better forum than the Wordpress forum software.
Most developers will be able to port a forum design to a WordPress design. I've done it several times. I don't consider myself a WordPress developer or designer. WordPress is nothing fancy, it's simple PHP and there is extensive documentation online for building themes... nothing too taxing for a full stack developer.
Go for whatever you want... but don't forget to stipulate to your designers exactly what you want and don't want... otherwise, you'll just end up getting shafted... i.e. they'll do exactly what @fisicx has suggested and charge you a princely sum for doing it.
You can try Upwork, but might take a while to find a good one. My team has a good Wordpress guy as well. You can drop him a message here: nnikolaev at sematigo.co.uk
The essence of the OP's issue is find a trustworthy supplier. This is tricky for any service isn't it, whether it is a WordPress designer or a Kitchen fitter? The normal approach is research then ask for references then follow up references.
I think you probably can look for a company who can do you both, forum and WordPress. It would be easier. But if you only need a WordPress designer, I think you either can buy and download one of the customized themes from popular websites like templatemonster or find a specialist from Upwork or Behance.
I agree with fisicx, at first ready made themes and plugins will be enough and once you start getting traction you can always pay professionals to help improve its design.