I"m looking into doing the same.
It looks like its just going to be using photos from other builds and experimenting.
The great thing about making this is there is always room for improvement and detail as i've learnt from building the t21 and the dlt19.
After looking into this one for sometime, it should be a easy one ;-).
You can't put a cost on making these as everyone would need to look for other options to create their weapon of choice.