The Cambridge exam board is refining its alternative qualification for students aiming for top universities.
Concerns have been raised about existing A-levels
From 2008 the Pre-U exam would involve studying three subjects over two years, with final exams and an extended essay.
Unlike AS or A-levels, it would not be modular and split into two parts, nor require everyone to do certain subjects like the International Baccalaureate.
The announcement came as an academic said ministers were "in denial" about A-levels having got easier.
The government insisted standards were rising "year on year".
But Dr Robert Coe, an education specialist from Durham University who has analysed trends, said A-levels were no longer "fit for purpose" in challenging or distinguishing between the brightest pupils.
"I don't think it is a scandal that they are easier. What I think is a scandal is that they have become easier but that official sources are in denial about it."
The University of Cambridge International Examinations (CIE) said it had developed the Pre-U - first announced last October - in response to demand from teachers wanting to prepare students for higher education more effectively.
It is being developed with independent schools and Russell Group universities and a specialist school representative.
Universities had also expressed concern about students' capacity for the more independent style of learning they required, CIE said.
The intention is to have syllabuses available in September next year for first teaching a year later.
CIE's chief executive, Ann Puntis, said those involved in the talks about the new qualification so far had been "very excited".
"We have been very impressed with the amount of support that the new qualification has been receiving," she said.
Ms Puntis said Pre-U students would be expected to take three subjects and a subsidiary.
They could "mix and match" with A-levels if they chose - the Pre-U would not feature art and design, for example.
"Universities are telling us that they will really value a student who has done the whole qualification," Ms Puntis said.
"But in this first phase we recognise schools will want to continue with some syllabuses that lie outside the 19 we are making available."
She said CIE was in talks with the Qualifications and Curriculum Authority about getting the Pre-U accredited for use in state schools.
Gifted and talented
Some schools are deliberately ignoring calls to make sure the brightest children fulfil their potential, according to Deborah Eyre, director of the National Academy for Gifted and Talented Youth.
Writing in the Times Educational Supplement, she said they had not understood how important it was to nurture gifted children.
"A minority of schools, however, have deliberately chosen not to prioritise this agenda, saying it is divisive," Prof Eyre said.
They mistakenly believed the current system was equitable.
"The winners in the current school system are the middle-class and the socially advantaged."