Intel is planning to invest $300 million to create what it’s calling a new form of computer to bridge the (somewhat slender) gap between a netbook and a tablet.

According to the company, the Russian doll-like sequence of laptop/notebook/netbook/tablet needs a new family member: the Ultrabook. As is usually the case with hybrid devices, the idea is to take the best parts of two concepts: the instant switch-on, slimline build and lengthy battery life of the tablet, with the processing power and “full” computing of the netbook.

How you make a full-fledged computer with a battery life that covers all-day use and multiple days on standby, while still making it portable, is in this case the $400 question. Intel is going to work on its own processors to try to cut power use, but is also ready to put money into hardware and software companies with relevant ideas.

You certainly can’t accuse Intel of a lack of ambition: not only does it believe it can make such devices available before Christmas for under $1,000, but it reckons that by the end of 2012, 40 percent of all consumer laptops will be in the “Ultrabook” category. It’s not clear if that refers to manufacture or sales: it’s hard to imagine laptops that are anywhere close to a thousand bucks making up 40 percent of sales.

The plan is to release the new models in waves, the first of which will effectively be souped up, slimmed-down and always-connected netbooks, while the second will combine keyboards with a touchscreen and will likely run Windows 8.

And if any of this sounds familiar, Intel has flat-out admitted that one of the goals is to have a competitor for the MacBook Air at far below Apple prices.

The New York Times notes that Intel has already released guidelines on suitable designs for manufacturers to use chips specifically designed for “Ultrabooks.” The problem is that manufacturers working to the first design are struggling to get the device below the $1,000 barrier.