Dell is already selling computers with Ubuntu pre-loaded on them, Lenovo is getting ready to sell Thinkpad laptops with SLED 10 on them.
We should expect Dell to make its Ubuntu computers available outside the US before Christmas and other manufacturers to start selling Linux as well.
Philippe Lotz is looking at the possibility for Linux Mint to sell its own computers. Nothing is for sure yet. The chosen manufacturer is likely to be MSI/Medion.