I've made a few suggestions along those lines but I haven't tested any of them in play.
My current version of the idea is:
24 points ECL -1
30 points ECL 0
36 points ECL 1
However, I'd be very careful with ECL -1. For non-magic using classes, it would probably be balanced but I don't think it would be balanced to have 2nd level characters casting 2nd level spells. I don't know how well it would work for 4th level characters to be casting fireballs either. It probably wouldn't make too much difference but it might well make "options" like ECL 0 sorcerors into mere illusions. So it might be a good idea to restrict the ECL -1 option to NPC classes and non-casting classes.