You should go to a few stores and figure out the speakers first. Wharfedale Lintons are attractive speakers, but they are not as clear and resolving as many other speakers. In a 12x12 room, I would worry about the space you can give them as they are rear ported as well. You may have better luck with a few other options from Elac or JBL, or the KLH Model 3 or 5.
You can absolutely get a great integrated for $5K or less, especially on the used market. Check out Primaluna. The Primaluna HP Dialogue is an older model but sounds nearly as good as the latest top model and will beat out many other amp separates up to $10K+, and you can find the amp used generally for $3K. You can then invest the rest in better tubes, cables, etc. The headphone section on the unit is also superb, as it uses the full tube stage for the output.