Hm.  When I grew out my color, I cut it all off when it reached two inches.  However, this is what I did to get it to that point.  My roots were dark, so I got lowlights, but you would just get highlights. 

Each time I got it colored, I got more lowlights and fewer highlights, so I gradually transitioned to darker and darker hair.  I would think the same would work in reverse.  What you are trying to avoid is that horizontal strip from grown out color.

Another thing you could do is tea rinses until you've grown out enough that you can stop. Hibiscus worked for me to make a reddish color. Tea rinses will wash right out with your next shampoo.

Here's my before and after:
Before:
http://forums.longhaircommunity.com/picture.php?albumid=423&pictureid=9743

After a hibiscus tea rinse:
http://forums.longhaircommunity.com/picture.php?albumid=423&pictureid=9751

It depends on your pH though. For some people hibiscus ends up kind of purple/blue. But, I think there are other herbal rinses that can impart red color too.

Mellie

Edited by Bikerbraid to remove the [img] tags which only work on jpg or bitmap types