I have never seen the Nixim before, didn't realise they made cockpits!
I had a Gamepod GTX and the frames I now design sort of followed on from the experience I had with the GTX, Something compact but with the ease of customising each frame and upgrading parts as required.
For a DIY kit, prices start around £400 depending on options, the frame above handles PC tower, triple screens, surround sound etc and is almost the same as what I am using now. Very stable and will last for years, I am looking to customise mine even further by integrating the pc into the actual frame as a one off project.
I can get our Monacos embroidered with gamertags etc and even different buckets can be chosen depending on your requirements. These are going to be the ultimate profile rigs when we get a full range up for retail with everything from basic wheel mounts through to fully enclosed cockpits that will be suitable for racing and flight sims, even working on a 5 screen model as we speak.
Also looking at powder coating, floor pans etc, every conceivable idea will be integrated into our top end models.
I am also working with a wheel supplier to get a model prepared featuring their products for retail.