Thanks for your reply.
We do in part duplicate it to get the correct price in the first place obviously, but I don't believe there is any kind of 'standard' to how the pricing is produced. Therefore I couldn't replicate it fully, and this would mean a pricing update would have to be done twice. I think pulling from the external system is the only option.
I've been messing with product variants, and it seems like I could use them to create variants on the fly rather than new SKUs. This would have the benefit of allowing SKUs to existing with the kentico tree, but no other benefits. Is there a particular reason why variants (with customer id for example) wouldn't work for us?
Actually half way through typing this, I've seen something else.... If I continue to auto-create skus on the fly, if I set a parent SKU ID, does this prevent them appearing in the products app?
In summary, the main reason for wanting to change is because I want to use the Kentico tree, and products rather than our old 'productdetail' query string powered page (for SEO reasons, and other stuff). However the 'real' skus would merge with our created 'fakse' sku's which wouldn't be good for the end admin users!